Moving picture coding method, moving picture decoding method, moving picture coding apparatus, moving picture decoding apparatus, and moving picture coding and decoding apparatus

ABSTRACT

A moving picture coding method includes: performing context adaptive binary arithmetic coding in which a variable probability value is used, on first information among multiple types of sample adaptive offset (SAO) information used for SAO that is a process of assigning an offset value to a pixel value of a pixel included in an image generated by coding the input image; and continuously performing bypass arithmetic coding in which a fixed probability value is used, on second information and third information among the multiple types of the SAO information, wherein the coded second and third information are placed after the coded first information in the bit stream.

FIELD

The present disclosure relates to a moving picture coding method and amoving picture decoding method.

BACKGROUND

The High Efficiency Video Coding (HEVC) standard, a next-generationimage coding standard, has been examined in various ways to increase itscoding efficiency (Non Patent Literature (NPL) 1). In addition, theInternational Telecommunication Union Telecommunication Standardizationsector (ITU-T) standard typified by H.26x, and the ISO/IEC standardtypified by MPEG-x exist conventionally. The latest and most advancedimage coding standard has been examined as a standard next to a standardcurrently typified by H.264/AVC or MPEG-4 AVC (see Non Patent Literature(NPL) 2).

In the HEVC standard, coding degradation reduction processing referredto as sample adaptive offset (SAO) has been examined to further reducecoding degradation (a difference between an original signal beforecoding and a coded and decoded signal). The SAO is offset processing inwhich an offset value is added for each of predetermined regions,categories, or types, to reduce the coding degradation, and is performedon a provisionally decoded image (reconstructed image) (see Non PatentLiterature (NPL) 3).

CITATION LIST Non Patent Literature

-   [NPL 1] Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T    SG16 WP3 and ISO/IEC JTC1/SC29/WG11 9th Meeting: Geneva, CH, 27    Apr.-7 May 2012, JCTVC-I1003_d1, “High efficiency video coding    (HEVC) text specification draft 7”-   [NPL 2] ITU-T Recommendation H.264 “Advanced video coding for    generic audiovisual services”, March, 2010-   [NPL 3] Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T    SG16 WP3 and ISO/IEC JTC1/SC29/WG11 9th Meeting: Geneva, CH, 27    Apr.-7 May 2012, JCTVC-I0602, “BoG report on integrated text of SAO    adoptions on top of JCTVC-I0030”

SUMMARY Technical Problem

However, a moving picture coding method and a moving picture decodingmethod using the SAO of NPL 3 cannot make processing efficient.

In view of this, one non-limiting and exemplary embodiment provides amoving picture coding method and a moving picture decoding method thatcan make processing efficient.

Solution to Problem

A moving picture coding method according to an aspect of the presentdisclosure is a moving picture coding method for coding an input imageto generate a bit stream, the method including: performing contextadaptive binary arithmetic coding in which a variable probability valueis used, on first information among multiple types of sample adaptiveoffset (SAO) information used for SAO that is a process of assigning anoffset value to a pixel value of a pixel included in an image generatedby coding the input image; and continuously performing bypass arithmeticcoding in which a fixed probability value is used, on second informationand third information among the multiple types of the SAO information,wherein the coded second and third information are placed after thecoded first information in the bit stream.

These general and specific aspects may be implemented using a system, amethod, an integrated circuit, a computer program, or acomputer-readable recording medium such as a CD-ROM, or any combinationof systems, methods, integrated circuits, computer programs, orcomputer-readable recording media.

Additional benefits and advantages of the disclosed embodiments will beapparent from the Specification and Drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the Specification and Drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

Advantageous Effects

A moving picture coding method and a moving picture decoding method inthe present disclosure can make processing efficient.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the disclosure willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate a specificembodiment of the present disclosure.

FIG. 1A is a table showing information used for offset processingreferred to as SAO.

FIG. 1B is a table showing other information used for offset processingreferred to as SAO.

FIG. 1C is a table showing other information used for offset processingreferred to as SAO.

FIG. 1D is a table showing other information used for offset processingreferred to as SAO.

FIG. 2 is a block diagram showing a functional configuration of a SAOinformation decoding unit.

FIG. 3 is a flow chart showing an operation flow of the SAO informationdecoding unit.

FIG. 4 is a flow chart showing context adaptive binary arithmeticdecoding.

FIG. 5 is a flow chart showing bypass arithmetic decoding.

FIG. 6 is a flow chart showing a normalization process in an arithmeticdecoding method.

FIG. 7 is a block diagram showing an exemplary configuration of a movingpicture decoding apparatus according to Embodiment 1.

FIG. 8 is a block diagram showing a functional configuration of a SAOinformation decoding unit according to Embodiment 1.

FIG. 9 is a flow chart showing arithmetic decoding by the SAOinformation decoding unit according to Embodiment 1.

FIG. 10A is a diagram for illustrating, in Embodiment 1, an exemplarysequence of parameters included in SAO information, and an exemplarydecoding order of the parameters.

FIG. 10B is a diagram corresponding to the flow chart of FIG. 3 and forillustrating an exemplary sequence of parameters included in SAOinformation, and an exemplary decoding order of the parameters.

FIG. 10C is a diagram for illustrating, in Embodiment 1, anotherexemplary sequence of parameters included in SAO information, andanother exemplary decoding order of the parameters.

FIG. 11 is a block diagram showing an exemplary configuration of amoving picture decoding apparatus according to Embodiment 2.

FIG. 12 is a flow chart showing arithmetic coding by a SAO informationcoding unit according to Embodiment 2.

FIG. 13A is a table showing a syntax for generating a conventional bitstream.

FIG. 13B is a table showing a syntax for generating a bit stream inEmbodiment 2.

FIG. 14 is a table showing a syntax for generating another bit stream inEmbodiment 2.

FIG. 15A is a flow chart for a moving picture coding method in anembodiment.

FIG. 15B is a block diagram showing a moving picture coding apparatus inan embodiment.

FIG. 15C is a flow chart for a moving picture decoding method in anembodiment.

FIG. 15D is a block diagram showing a moving picture decoding apparatusin an embodiment.

FIG. 16 is an overall configuration diagram of a content providingsystem that provides content distribution services.

FIG. 17 is an overall configuration diagram of a digital broadcastingsystem.

FIG. 18 is a block diagram showing an exemplary configuration of atelevision.

FIG. 19 is a block diagram showing an exemplary configuration of aninformation reproducing/recording unit that reads and writes informationfrom and on a recording medium that is an optical disk.

FIG. 20 is a diagram showing an exemplary configuration of a recordingmedium that is an optical disk.

FIG. 21A is a diagram showing an exemplary cellular phone.

FIG. 21B is a block diagram showing an exemplary configuration of acellular phone.

FIG. 22 is a diagram showing a structure of multiplexed data.

FIG. 23 is a diagram schematically showing how each stream ismultiplexed in multiplexed data.

FIG. 24 is a diagram showing how a video stream is stored in a stream ofPES packets in more detail.

FIG. 25 is a diagram showing a structure of TS packets and sourcepackets in multiplexed data.

FIG. 26 is a diagram showing a data structure of a PMT.

FIG. 27 is a diagram showing an internal structure of multiplexed datainformation.

FIG. 28 is a diagram showing an internal configuration of streamattribute information.

FIG. 29 is a flow chart showing steps for identifying video data.

FIG. 30 is a block diagram showing an exemplary configuration of anintegrated circuit that performs the moving picture coding method andthe moving picture decoding method according to each of embodiments.

FIG. 31 is a diagram showing a configuration for switching betweendriving frequencies.

FIG. 32 is a flow chart showing steps for identifying video data andswitching between driving frequency.

FIG. 33 is an exemplary look-up table in which video data standards areassociated with driving frequencies.

FIG. 34A is a diagram showing an exemplary configuration for sharing amodule of a signal processing unit.

FIG. 34B is a diagram showing another exemplary configuration forsharing a module of a signal processing unit.

DESCRIPTION OF EMBODIMENTS

(Underlying Knowledge Forming Basis of the Present Disclosure)

FIGS. 1A to 1D are diagrams showing four types of information used foroffset processing referred to as SAO. These four types of information(parameters) are SAO type information (sao_type_idx), SAO pixel valueband position information (sao_band_position), a SAO offset value(sao_offset[i]), and a SAO offset sign (sao_offset_sign[i]). It is to benoted that these information items are collectively referred to as SAOinformation.

As shown in FIG. 1A, the SAO type information (sao_type_idx) indicatesnot performing offset processing or a type of offset processing to beperformed. Examples of the offset processing include edge offset inwhich offset processing is performed on a pattern in an edge directionand band offset in which offset processing is performed on pixel valuesincluded in a certain band (range of predetermined pixel values). Inaddition, the edge offset is further classified into several typesdepending on edge directions. For instance, in NPL 3, contents indicatedby SAO type information are classified into six types as shown in FIG.1A. Arithmetic coding (context adaptive binary arithmetic coding) isperformed on part of the SAO type information using a contextcorresponding to a variable probability value, and the part of the SAOtype information is stored in a bit stream.

The SAO pixel value band position information (sao_band_position) isinformation used for the band offset. For example, the level band (0 to255 in the case of 8 bits) of an image signal to be processed is dividedinto 32 sections. The SAO pixel value band position informationindicates from which section the band offset is applied to a section (atleast one continuous section) among the 32 sections. For instance, inNPL 3, the number of continuous sections is four. When the SAO pixelvalue band position information indicates 1 and the image signal has 8bits, the SAO pixel value band position information indicates that theoffset processing is performed on the sections of pixel values 8 to 15,pixel values 16 to 23, pixel values 24 to 31, and pixel values 32 to 39.As shown by “XXXXX” in FIG. 1B, the SAO pixel value band positioninformation has a fixed length of 5 bits, is coded by bypass arithmeticcoding using not a variable probability value but a fixed probabilityvalue, and is stored in a bit stream.

The SAO offset value (sao_offset[i]) indicates the type of the edgeoffset indicated by the SAO type information or an offset value actuallygiven to the section (the at least one continuous section) indicated bythe SAO pixel value band position information. It is to be noted iindicates one of the types or sections. To put it another way, the SAOoffset value indicates, for each i, an offset value corresponding to atype of the edge offset or a section of the band offset indicated by thei. For example, in NPL 3, the i takes one of four values from 0 to 3.Stated differently, in the case of an offset value for the edge offset,the SAO offset value indicates, for each edge direction (each of 0, 45,90, and 135 degrees), a value from 0 to 7 for a corresponding one offour types of patterns (e.g., V type, A type, / type, and \ type) as theoffset value. In the case of an offset value for the band offset, theSAO offset value indicates a value from 0 to 7 for a corresponding oneof the four sections as the offset value. Then, the arithmetic coding isperformed on part of the SAO offset value using the context, and isstored in a bit stream. (refer to FIG. 1C)

The SAO offset sign (sao_offset_sign[i]) indicates the sign of the SAOoffset value. It is to be noted that i is the same as the i used for theSAO offset value, and associates a SAO offset value and a SAO offsetsign. For instance, in NPL 3, when the SAO type information indicatesthe edge offset, the SAO sign is not used, and an offset value indicatedby the SAO offset value is handled as always being positive. Thus, theSAO offset sign is not described in a bit stream. In contrast, when theSAO type information indicates the band offset, SAO offset signs areused for respective SAO offset values of the four sections. Thus, theSAO offset signs are coded by the bypass arithmetic coding, and arestored in the bit stream. (refer to FIG. 1D)

The following describes a conventional example of a method for decodingSAO information (the four types), with reference to FIG. 2 and FIG. 3.

FIG. 2 is a block diagram showing a functional configuration of a SAOinformation decoding unit.

A SAO information decoding unit A01 performs variable length decoding(arithmetic decoding) on the SAO type information (sao_type_idx), theSAO pixel value band position information (sao_band_position), the SAOoffset value (sao_offset[i]), and the SAO offset sign(sao_offset_sign[i]) that are included in the SAO information.

The SAO information decoding unit A01 includes: a Sao_Type decoding unitA02 that decodes SAO type information; a Sao_Type determining unit A03that determines a type of offset processing or the like indicated by theSAO type information; switches A04, A05, and A06; a Sao_band_positiondecoding unit A07 that decodes SAO pixel value band positioninformation; a Sao_Offset decoding unit A08 that decodes a SAO offsetvalue; a Sao_offset_sign decoding unit A09 that decodes a SAO offsetsign; a data storage position setting unit A10; and a data storage unitA11. The SAO information decoding unit A01 restores SAO information froma bit stream BS.

The operation of the SAO information decoding unit A01 is described indetails with reference to FIG. 3.

FIG. 3 is a flow chart showing an exemplary operation flow of the SAOinformation decoding unit A01.

First, the Sao_Type decoding unit A02 of the SAO information decodingunit A01 decodes SAO type information (sao_type_idx) from a bit streamBS (SB01). Next, the Sao_Type determining unit A03 determines whether ornot the sao_type_idx indicates band offset in which offset processing isperformed on pixel values included in a certain band (range ofpredetermined pixel values) (SB02). When determining that the bandoffset is indicated (YES in SB02), the Sao_Type determining unit A03turns the switch A04 ON. With this, the Sao_band_position decoding unitA07 decodes SAO pixel value band position information(sao_band_position) (SB03). The data storage position setting unit A10determines a storage position in the data storage unit A11 based on thedecoded SAO pixel value band position information. In contrast, whendetermining that the band offset is not indicated (NO in SB02), theSao_Type determining unit A03 turns the switch A04 OFF. Next, theSao_Type determining unit A03 determines whether or not the sao_type_idxindicates that the offset processing is not to be performed (Sao off)(SB04). Here, when determining that Sao off is indicated (YES in SB04),the Sao_Type determining unit A03 turns the switches A04, A05, and A06OFF, and terminates decoding of the SAO information.

In contrast, when determining that Sao off is not indicated (NO inSB04), the Sao_Type determining unit A03 turns the switch A05 ON. Withthis, the Sao_Offset decoding unit A08 decodes a SAO offset value(sao_offset) from the bit stream BS (SB05). It is to be noted that thedecoded SAO offset value is stored at the position in the data storageunit A11 set by the data storage position setting unit A10. Here, thedecoding in the step SB05 is continued until a predetermined number ofSAO offset values is decoded (during a period of NO in SB06). When allthe SAO offset values are decoded (YES in SB06), the Sao_Typedetermining unit A03 determines whether or not the sao_type_idxindicates the band offset (SB07). When determining that the band offsetis indicated (YES in SB07), the Sao_Type determining unit A03 turns theswitch A06 ON.

With this, when the decoded SAO offset value is not zero (NO in SB08),the Sao_offset_sign decoding unit A09 decodes a SAO offset signcorresponding to the SAO offset value (SB09). In this case, the SAOoffset value in the data storage unit A11 is updated using the decodedSAO offset sign. When the decoded SAO offset value is zero (YES inSB08), the SAO offset sign has no particular meaning, and thus theSao_offset_sign decoding unit A09 skips the decoding. Here, theSao_offset_sign decoding unit A09 continues the decoding until apredetermined number of SAO offset signs corresponding to SAO offsetvalues is decoded (during a period of NO in SB10). When all the SAOoffset signs are decoded (YES in SB10), the SAO information decodingunit A01 terminates the decoding of the SAO information.

It is to be noted that parameters that are information items decoded insteps enclosed by double frame lines in FIG. 3 are parameters decoded bybypass arithmetic decoding in which a variable probability value is notnecessary. Parameters that are information items decoded in stepsenclosed by regular frame lines are parameters that are informationitems decoded using a variable probability value that is at least partof each of the parameters, and are dispersed in a bit stream.

The following describes variable length coding such as context adaptivebinary arithmetic coding using a variable probability value and bypassarithmetic coding not using a variable probability value. In H.264 orHEVC, the context adaptive binary arithmetic coding (CABAC) is one ofvariable length coding techniques. The CABAC is described below withreference to FIG. 4, FIG. 5, and FIG. 6.

FIG. 4 is a flow chart showing context adaptive binary arithmeticdecoding. It is to be noted that FIG. 4 is excerpted from NPL 2, and isas described in NPL 2, unless otherwise explained.

In the context adaptive binary arithmetic decoding, first, a context(ctxIdx) determined based on a signal type is inputted.

Next, the value “qCodIRangeIdx” is calculated from the first parameter“codIRange” showing a current state in a arithmetic decoding apparatus,and pStateIdx that is a state value corresponding to ctxIdx is obtained.codIRangeLPS is obtained by referring to a table (rangeTableLPS) usingthe two values. It is to be noted that the codIRangeLPS is a parametershowing a state in the arithmetic decoding apparatus when LPS (indicatesa symbol having a low occurrence probability among symbols 0 and 1)occurs with respect to the first parameter “codIRange” showing the statein the arithmetic decoding apparatus.

A value obtained by subtracting the codIRangeLPS from current codIRangeis put into the codIRange (step SC01). Next, the calculated codIRange iscompared to the second parameter “codIOffset” showing a state in thearithmetic decoding apparatus (step SC02). When the codIOffset isgreater than or equal to the codIRange (Yes in SC02), it is determinedthat an LPS symbol has occurred, and a value (when valMPS=1, 0; and whenvalMPS=0, 1) different from valMPS (which is a specific value indicatinga symbol having a high occurrence probability among symbols 0 and 1, andindicates 0 or 1) is set to binVal that is a decoded output value.Moreover, a value obtained by subtracting the codIRRangeLPS from thecodIRange is set to the second parameter “codIOffset” showing the statein the arithmetic decoding apparatus. Because LPS has occurred, thevalue of the codIRangeLPS calculated in step SC01 is set to the firstparameter “codIRange” showing the state in the arithmetic decodingapparatus (step SC03). It is to be noted that because a case wherepStateIdx that is a state value corresponding to the ctxIdx is 0 (Yes instep SC05) indicates a case where the probability of the LPS is greaterthan that of MPS, the valMPS is replaced with the different value (whenvalMPS=1, 0; and when valMPS=0, 1) (step SC06). In contrast, when thepStateIdx is not 0 (No in step SC05), the pStateIdx is updated based onthe translation table when the LPS occurs (step SC07).

When the codIOffset is small (No in SC02), it is determined that an theMPS symbol has occurred, the valMPS is set to the binVal, the decodedoutput value, and the pStateIdx is updated based on the translationtable “transIdxMPS” when the MPS occurs (step SC04).

Lastly, a normalization process (RenormD) is performed (step SC08), andthe context adaptive binary arithmetic decoding is terminated.

As above, in the context adaptive binary arithmetic decoding, becausesymbol occurrence probabilities (probability values), binary symboloccurrence probabilities, are held in association with context indexes,and are switched according to conditions (e.g., by referring to thevalue of an adjacent block), it is necessary to maintain a processingorder.

FIG. 5 is a flow chart showing bypass arithmetic decoding. It is to benoted that FIG. 5 is excerpted from NPL 2, and is as described in NPL 2,unless otherwise explained.

First, the second parameter “codIOffset” showing the current state inthe arithmetic decoding apparatus is shifted to the left (doubled), 1bit is read from a bit stream, and when the read bit has 1, 1 is furtheradded to the (doubled) value, and when the read bit has 0, the (doubled)value is set (SD01).

Next, when the codIOffset is greater than or equal to the firstparameter “codIRange” showing the state in the arithmetic decodingapparatus (Yes in SD02), “1” is set to the binVal, the decoded outputvalue, a value obtained by subtracting the codIRange from the codIOffsetis set to the codIOffset (step SD03). In contrast, when the codIOffsetis less than the first parameter “codIRange” showing the state in thearithmetic decoding apparatus (No in SD02), “0” is set to the binVal,the decoded output value (step SD04).

FIG. 6 is a flow chart for illustrating in more detail the normalizationprocess (RenormD) in step SC08 shown in FIG. 4. It is to be noted thatFIG. 6 is excerpted from NPL 2, and is as described in NPL 2, unlessotherwise explained.

In the context adaptive binary arithmetic decoding, when the firstparameter “codIRange” showing the state in the arithmetic decodingapparatus becomes less than 0x100 (hexadecimal: 256 (decimal)) (Yes instep SE01), the codIRange is shifted to the left (doubled), the secondparameter “codIOffset” showing the state in the arithmetic decodingapparatus is shifted to the left (doubled), 1 bit is read from a bitstream, and when the read bit has 1, 1 is further added to the (doubled)value, and when the read bit has 0, the (doubled) value is set (SE02).

When the codIRange finally becomes greater than or equal to 256 throughthis process (No in step SE01), the normalization process is terminated.

The arithmetic decoding is performed by performing the above steps.

However, as stated above, because importance is placed on enhancement ofdata storability in the method shown in NPL 3, a parallel processingcapability in the arithmetic coding or arithmetic decoding, arrangementof coded bits, or the like is insufficient, and a redundant bit lengthis necessary. As a result, a burden is imposed on the coding anddecoding of SAO information.

In view of the above, the present disclosure provides a moving picturecoding method, a moving picture coding apparatus, a moving picturedecoding method, a moving picture decoding apparatus, and so on whichcan make processing efficient without reducing coding efficiency whilemaintaining the data storability, when the arithmetic coding orarithmetic decoding is performed on the SAO information that isinformation necessary for SAO. It is to be noted that hereinafter, theremay be a case where the term “coding” is used in the sense of“encoding.”

A moving picture coding method according to an aspect of the presentdisclosure is a moving picture coding method for coding an input imageto generate a bit stream, the method including: performing contextadaptive binary arithmetic coding in which a variable probability valueis used, on first information among multiple types of sample adaptiveoffset (SAO) information used for SAO that is a process of assigning anoffset value to a pixel value of a pixel included in an image generatedby coding the input image; and continuously performing bypass arithmeticcoding in which a fixed probability value is used, on second informationand third information among the multiple types of the SAO information,wherein the coded second and third information are placed after thecoded first information in the bit stream.

Here, the context adaptive binary arithmetic coding cannot be performedin parallel, and the bypass arithmetic coding can be performed inparallel on a bit basis. Thus, in the moving picture coding methodaccording to the aspect of the present disclosure, because the bypassarithmetic coding of the second information and the bypass arithmeticcoding of the third information are performed not intermittently butcontinuously due to the context adaptive binary arithmetic coding of thefirst information, it is possible to increase an amount of informationthat can be processed in parallel. As a result, it is possible to makethe parallel processing efficient. For instance, it is possible toincrease a parallel processing capability by increasing the number ofbits on which the bypass arithmetic coding is performed in parallel.Moreover, because a probability value is fixed in the bypass arithmeticcoding, it is possible to previously perform, before a symbol to becoded is obtained, arithmetic coding when the symbol is 0 and arithmeticcoding when the symbol is 1 in parallel. In other words, it is possibleto previously perform, for each occurrence pattern of symbol, arithmeticcoding corresponding to the occurrence pattern. To put it differently,it is possible to previously perform look-ahead processing in the bypassarithmetic coding. Thus, it is possible to effectively use thelook-ahead processing by continuously performing the bypass arithmeticcoding of the second information and the bypass arithmetic coding of thethird information.

Furthermore, because, in the bit stream generated by the moving picturecoding method according to the aspect of the present disclosure, thesecond and third information on which the bypass arithmetic coding isperformed are placed after the first information on which the contextadaptive binary arithmetic coding is performed, without being divided bythe first information, the moving picture decoding apparatus is alsoallowed to easily decode the second and third information continuouslyby bypass arithmetic decoding. As a result, it is also possible to makethe parallel processing efficient when the decoding is performed.Moreover, because, in the bit stream, the first information on which thecontext adaptive binary coding is performed is placed before the secondand third information on which the bypass arithmetic coding isperformed, the moving picture decoding apparatus is allowed to startbypass arithmetic decoding of the second information and bypassarithmetic decoding of the third information before context adaptivebinary arithmetic decoding of the first information. As a result, themoving picture decoding apparatus is capable of start decoding thesecond and third information before the end of decoding of the firstinformation. With this, it is possible to increase the speed ofprocessing.

Moreover, one of the second information and the third information may besao_band_position indicating a range of pixel values to which the SAO isapplied.

With this, it is possible to efficiently code the sao_band_position.Moreover, for instance, when the first information is the sao_offsetindicating the absolute value of an offset value, the sao_band_positionis placed after the sao_offset in the bit stream. With this, in themoving picture decoding apparatus, because the sao_band_position isdecoded after the sao_offset, even when the sao_offset is decoded, aslong as the sao_band_position is not decoded, it is not possible tostore the decoded sao_offset at a storage position in a memoryassociated with a range (position) of pixel values indicated by thesao_band_position. However, it is possible to appropriately apply theabsolute value of the offset value indicated by the sao_offset to pixelsvalues included in the range of pixel values indicated by thesao_band_position, by storing the decoded sao_offset in the memoryregardless of the range and associating the decoded sao_offset with thesao_band_position to be decoded. As a result, it is possible to make theprocessing efficient and properly perform the SAO.

Moreover, the other of the second information and the third informationmay be sao_offset_sign indicating whether an offset value is positive ornegative, the offset value being assigned to a pixel value to which theSAO is applied.

With this, it is possible to efficiently code the sao_offset_sign.Moreover, for example, when the first information is the sao_offsetindicating the absolute value of the offset value, the sao_band_sign isplaced after the sao_offset in the bit stream. Here, when the absolutevalue of the offset value indicated by the sao_offset is 0, it ispossible to omit the sao_offset_sign. As a result, it is possible toincrease coding efficiency.

Moreover, in the continuously performing, the sao_band_position may becoded after the sao_offset_sign is coded.

With this, for instance, when the first information is the sao_offsetindicating the absolute value of the offset value, the sao_offset, thesao_offset_sign, and the sao_band_position are placed in the bit streamin this order. As a result, the moving picture decoding apparatus makesit possible to decode the sao_offset and the sao_offset_sign before thesao_band_position, and is thus capable of quickly determining an offsetvalue assigned to a pixel value without waiting the decoding of thesao_band_position. Consequently, it is possible to readily store theoffset value into the memory.

Moreover, a pixel to which the SAO is applied may include components ofmultiple types, and the first information, the second information, andthe third information may be coded for each of the components.

With this, for example, when the components of the multiple types are aluminance and a chrominance, in the bit stream, coded first informationapplied to the luminance and coded second information and coded thirdinformation applied to the luminance are collectively placed, and codedfirst information applied to the chrominance and code second informationand coded third information are collectively placed. As a result, themoving picture decoding apparatus makes it possible to decode only oneof SAO information applied to the luminance and SAO information appliedto the chrominance as necessary. In other words, when the SAO isperformed only on the luminance, it is possible to prevent the SAOinformation applied to the chrominance from being unnecessarily decoded.As a result, it is possible to make the processing efficient.

Moreover, in the continuously performing, the bypass arithmetic codingmay be further performed on at least one other information among themultiple types of the SAO information immediately before or immediatelyafter the coding of the second information and the third information.

With this, it is possible to further increase an amount of informationthat can be continuously processed in parallel, and thus it is possibleto make the parallel processing more efficient.

Moreover, the first information may be part of sao_type_idx indicatingthat the SAO is not to be performed or a type of the SAO.

With this, it is possible to prevent parallel processing efficiency forthe second information and the third information from decreasing due tothe context adaptive binary arithmetic coding of the sao_type_idx.

A moving picture decoding method according to another aspect of thepresent disclosure is a moving picture decoding method for decoding acoded image included in a bit stream, the method including: performingcontext adaptive binary arithmetic decoding in which a variableprobability value is used, on first information among multiple types ofSAO information that are included in the bit stream and used for sampleadaptive offset (SAO) which is a process of assigning an offset value toa pixel value of a pixel included in an image generated by decoding thecoded image; and continuously performing bypass arithmetic decoding inwhich a fixed probability value is used, on second information and thirdinformation that are among the multiple types of the SAO information andlocated after the first information in the bit stream.

Here, the context adaptive binary arithmetic decoding cannot beperformed in parallel, and the bypass arithmetic decoding can beperformed in parallel on a bit basis. Thus, in the moving picturedecoding method according to the other aspect of the present disclosure,because the bypass arithmetic decoding of the second information and thebypass arithmetic decoding of the third information are performed notintermittently but continuously due to the context adaptive binaryarithmetic decoding of the first information, it is possible to increasean amount of information that can be processed in parallel. As a result,it is possible to make the parallel processing efficient. For instance,it is possible to increase a parallel processing capability byincreasing the number of bits on which the bypass arithmetic decoding isperformed in parallel. Moreover, because a probability value is fixed inthe bypass arithmetic decoding, it is possible to previously perform,before data to be decoded is obtained, arithmetic decoding when thesymbol is 0 and arithmetic decoding when the symbol is 1 in parallel. Inother words, it is possible to previously perform, for each occurrencepattern of symbol, arithmetic decoding corresponding to the occurrencepattern. To put it differently, it is possible to previously performlook-ahead processing in the bypass arithmetic decoding. Thus, it ispossible to effectively use the look-ahead processing by continuouslyperforming the bypass arithmetic decoding of the second information andthe bypass arithmetic decoding of the third information.

Moreover, because, in the bit stream, the first information on which thecontext adaptive binary coding is performed is placed before the secondand third information on which the bypass arithmetic coding isperformed, it is possible to start context adaptive binary arithmeticdecoding of the first information before the bypass arithmetic decodingof the second information and the bypass arithmetic decoding of thethird information. As a result, it is possible to start decoding thesecond and third information before the end of decoding of the firstinformation. With this, it is possible to increase the speed ofprocessing.

Moreover, one of the second information and the third information may besao_band_position indicating a range of pixel values to which the SAO isapplied.

With this, it is possible to efficiently decode the sao_band_position.Moreover, for instance, when the first information is the sao_offsetindicating the absolute value of an offset value, the sao_band_positionis placed after the sao_offset in the bit stream. With this, because thesao_band_position is decoded after the sao_offset, even when thesao_offset is decoded, as long as the sao_band_position is not decoded,it is not possible to store the decoded sao_offset at a storage positionin a memory associated with a range (position) of pixel values indicatedby the sao_band_position. However, it is possible to appropriately applythe absolute value of the offset value indicated by the sao_offset topixels values included in the range of pixel values indicated by thesao_band_position, by storing the decoded sao_offset in the memoryregardless of the range and associating the decoded sao_offset with thesao_band_position to be decoded. As a result, it is possible to make theprocessing efficient and properly perform the SAO.

Moreover, the other of the second information and the third informationmay be sao_offset_sign indicating whether an offset value is positive ornegative, the offset value being assigned to a pixel value to which theSAO is applied.

With this, it is possible to efficiently decode the sao_offset_sign.Moreover, for example, when the first information is the sao_offsetindicating the absolute value of the offset value, the sao_band_sign isplaced after the sao_offset in the bit stream. Here, when the absolutevalue of the offset value indicated by the sao_offset is 0, thesao_offset_sign is omitted. As a result, it is possible to properlydecode the bit stream for which the coding efficiency is increased.

Moreover, in the continuously performing, the sao_band_position may bedecoded after the sao_offset_sign is decoded.

With this, for example, when the first information is the sao_offsetindicating the absolute value of the offset value, the sao_offset andthe sao_offset_sign are decoded before the sao_band_position, and thusan offset value assigned to a pixel value can be quickly determinedwithout waiting the decoding of the sao_band_position. Consequently, itis possible to readily store the offset value into the memory.

Moreover, a pixel to which the SAO is applied may include components ofmultiple types, and the first information, the second information, andthe third information may be coded for each of the components.

With this, for instance, when the components of the multiple types are aluminance and a chrominance, it is possible to decode only one of SAOinformation applied to the luminance and SAO information applied to thechrominance as necessary. In other words, when the SAO is performed onlyon the luminance, it is possible to prevent the SAO information appliedto the chrominance from being unnecessarily decoded. As a result, it ispossible to make the processing efficient.

Moreover, in the continuously performing, the bypass arithmetic decodingmay be performed on at least one other information among the multipletypes of the SAO information immediately before or immediately after thedecoding of the second information and the third information.

With this, it is possible to further increase an amount of informationthat can be continuously processed in parallel, and thus it is possibleto make the parallel processing more efficient. Moreover, the firstinformation may be part of sao_type_idx indicating that the SAO is notto be performed or a type of the SAO.

With this, it is possible to prevent parallel processing efficiency forthe second information and the third information from decreasing due tothe context adaptive binary arithmetic decoding of the sao_type_idx.

These general and specific aspects may be implemented using a system, amethod, an integrated circuit, a computer program, or acomputer-readable recording medium such as a CD-ROM, or any combinationof systems, methods, integrated circuits, computer programs, orcomputer-readable recording media.

Hereinafter, embodiments are specifically described with reference tothe Drawings.

Each of the embodiments described below shows a general or specificexample. The numerical values, shapes, materials, structural elements,the arrangement and connection of the structural elements, steps, theprocessing order of the steps etc. shown in the following embodimentsare mere examples, and therefore do not limit the scope of the Claims.Therefore, among the structural elements in the following embodiments,structural elements not recited in any one of the independent claims aredescribed as arbitrary structural elements.

Embodiment 1

FIG. 7 is a block diagram showing an exemplary configuration of a movingpicture decoding apparatus 100 according to Embodiment 1.

The moving picture decoding apparatus 100 decodes compression-codedimage data. For instance, coded image data (a bit stream) is inputted,on a block-by-block basis, to the moving picture decoding apparatus 100as signals to be decoded (input signals). The moving picture decodingapparatus 100 reconstructs image data by performing variable lengthdecoding, inverse quantization, and inverse transform on the inputtedsignals to be decoded.

As shown in FIG. 7, the moving picture decoding apparatus 100 includesan entropy decoding unit 110, an inverse quantization and inversetransform unit 120, an adder 125, a loop filter 130, a memory 140, anintra prediction unit 150, a motion compensation unit 160, and anintra/inter change switch 170.

The entropy decoding unit 110 performs variable length decoding on aninput signal, to reconstruct a quantization coefficient. It is to benoted that here, the input signal is a signal to be decoded, andcorresponds to coded image data for each block. Moreover, the entropydecoding unit 110 obtains motion data from the input signal, and outputsthe obtained motion data to the motion compensation unit 160.Furthermore, the entropy decoding unit 110 performs variable lengthdecoding on the input signal, to reconstruct SAO information, andoutputs the SAO information to the loop filter 130.

The inverse quantization and inverse transform unit 120 performs inversequantization on the quantization coefficient reconstructed by theentropy decoding unit 110, to reconstruct a transform coefficient. Then,the inverse quantization and inverse transform unit 120 performs inversetransform on the reconstructed transform coefficient, to reconstruct aprediction error.

The adder 125 adds the reconstructed prediction error to a predictionsignal, to generate a decoded image.

The loop filter 130 performs a loop filter process on the generateddecoded image. The decoded image on which the loop filter process hasbeen performed is outputted as a decoded signal. It is to be noted thatthe loop filter process includes SAO.

The memory 140 is a memory for storing reference images used for motioncompensation. Specifically, the memory 140 stores decoded images onwhich the loop filter process has been performed.

The intra prediction unit 150 performs intra prediction to generate aprediction signal (intra-prediction signal). Specifically, the intraprediction unit 150 performs intra prediction by referring to an imagearound a current block to be decoded (input signal) in the decoded imagegenerated by the adder 125, to generate an intra-prediction signal.

The motion compensation unit 160 performs motion compensation based onthe motion data outputted from the entropy decoding unit 110, togenerate a prediction signal (inter-prediction signal).

The intra/inter change switch 170 selects either the intra-predictionsignal or the inter-prediction signal, and outputs the selected signalto the adder 125 as a prediction signal.

The above configuration allows the moving picture decoding apparatus 100according to Embodiment 1 to decode the coded image data that is thecompression-coded image data.

It is to be noted that in Embodiment 1, the entropy decoding unit 110includes a SAO information decoding unit which decodes SAO information.

FIG. 8 is a block diagram showing a functional configuration of a SAOinformation decoding unit according to Embodiment 1.

A SAO information decoding unit 101 reconstructs SAO information from abit stream BS. In other words, the SAO information decoding unit 101performs variable length decoding on SAO type information(sao_type_idx), SAO pixel value band position information(sao_band_position), a SAO offset value (sao_offset[i]), and a SAOoffset sign (sao_offset_sign[i]) on which variable length coding hasbeen performed and that are included in the SAO information.

Specifically, the SAO information decoding unit 101 includes: a Sao_Typedecoding unit 102 that decodes SAO type information; a Sao_Typedetermining unit 103 that determines a type of offset processingindicated by the SAO type information or the like; switches 104 and 105;a Sao_band_position decoding unit 107 that decodes SAO pixel value bandposition information; a Sao_Offset decoding unit 108 that decodes a SAOoffset value; a Sao_offset_sign decoding unit 109 that decodes a SAOoffset sign; and a data storage unit 111.

The operation of the SAO information decoding unit 101 is described indetails with reference to FIG. 9.

FIG. 9 is a flow chart showing an exemplary flow of arithmetic decodingby the SAO information decoding unit 101.

First, the Sao_Type decoding unit 102 of the SAO information decodingunit 101 decodes SAO type information (sao_type_idx) from a bit streamBS (S201). Next, the Sao_Type determining unit 103 determines whether ornot the sao_type_idx indicates that SAO is not to be performed (Sao off)(S202). Here, when determining that the sao_type_idx indicates that theSAO is not to be performed (YES in S202), the Sao_Type determining unit103 turns the switches 104 and 105 OFF, and terminates arithmeticdecoding of SAO information, because the SAO information other than theSAO type information is not included in the bit stream BS.

In contrast, when determining that the sao_type_idx indicates that theSAO is to be performed (NO in S202), the Sao_Type determining unit 103turns the switch 105 ON. With this, the Sao_Offset decoding unit 108decodes a SAO offset value (sao_offset) from the bit stream BS (S203).It is to be noted that the Sao_Offset decoding unit 108 stores thedecoded SAO offset value into an offset register ensured in advance or amemory portion inside the data storage unit 111. Here, the Sao_Offsetdecoding unit 108 continues the decoding in step S203 until apredetermined number of SAO offset values is decoded (during a period ofNO in S204). When the Sao_Offset decoding unit 108 decodes all SAOoffset values (YES in S204), the Sao_Type determining unit 103determines whether or not the sao_type_idx indicates band offset inwhich offset processing is performed on pixel values included in acertain band (range of predetermined pixel values) (S205).

Here, when determining that the band offset is not indicated (NO inS205), the Sao_Type determining unit 103 turns the switch 104 OFF, andterminates arithmetic decoding of all SAO information. In contrast, whendetermining that the band offset is indicated (YES in S205), theSao_Type determining unit 103 turns the switch 104 ON. With this, whenthe decoded SAO offset value is not zero (NO in S206), theSao_offset_sign decoding unit 109 decodes a SAO offset signcorresponding to the SAO offset value (S207). In this case, the SAOoffset value in the data storage unit A11 is updated using the decodedSAO offset sign. When the decoded SAO offset value is zero (YES inS206), the SAO offset sign has no particular meaning, and thus theSao_offset_sign decoding unit 109 skips the decoding. Here, theSao_offset_sign decoding unit 109 continues the decoding until apredetermined number of SAO offset signs corresponding to SAO offsetvalues is decoded (during a period of NO in S208). When all SAO offsetsigns are decoded (YES in S208), the Sao_band_position decoding unit 107decodes SAO pixel value band position information (sao_band_position)(S209). The SAO pixel value band position information indicates whichoffset value of a pixel value band (section) the SAO offset value is,and thus the SAO pixel value band position information is stored intothe data storage unit 111. Alternatively, a storage position in the datastorage unit 111 is changed based on the SAO pixel value band positioninformation. This processing allows the SAO information to be decodedcorrectly.

It is to be noted that although the SAO type information is alwaysdecoded from the bit stream BS here, the present disclosure is notlimited to this. For instance, SAO type information in a region to beprocessed may be derived according to a predetermined rule (e.g., a rulethat SAO type information that is the same as SAO type information inthe left region is to be used), and the SAO type information may bedecoded. In this case, the SAO type information is not necessarilydescribed in a bit stream.

In this embodiment, because an order of multiple types of information(parameters) included in SAO information is different from an ordershown in FIG. 3, it is possible to reduce an amount of processing, makethe processing efficient, and properly decode a bit stream for whichcoding efficiency is increased.

It is to be noted that parameters that are information items decoded insteps enclosed by double frame lines in FIG. 9 are parameters decoded bythe bypass arithmetic decoding.

Parameters that are information items decoded in steps enclosed byregular frame lines are parameters on which context adaptive binaryarithmetic processing is performed using a variable probability valuethat is at least part of each of the parameters. In the moving picturedecoding method in this embodiment, as shown in FIG. 9, the parametersof the multiple types are decoded collectively (continuously) by bypassarithmetic decoding in the latter part of the bit stream BS incomparison with the method shown in FIG. 3.

It is to be noted that in the case of a parameter whose symboloccurrence probability is not approximately 50%, performing contextadaptive binary arithmetic coding in which a variable probability valueis used on the parameter makes it possible to increase the codingefficiency due to an information bias. For this reason, context adaptivebinary arithmetic decoding is performed on the parameter thus coded (seeFIG. 4). In contrast, in the case of a parameter whose possible valuehas a wide range or a parameter whose symbol occurrence probability isapproximately 50%, the symbol occurrence probability of the parameter isdeemed 50%, and it is possible to reduce an amount of processing byperforming bypass arithmetic coding on the parameter. In other words,performing bypass arithmetic decoding on a SAO offset sign correspondingto a SAO offset value and SAO pixel value band position information (seeFIG. 5) makes it possible to reduce the amount of processing. Inaddition, in this bypass arithmetic decoding, the normalization processis performed according to the flow shown in FIG. 6.

FIG. 10A is a diagram for illustrating, in this embodiment, an exemplarysequence of parameters included in SAO information, and an exemplarydecoding order of the parameters.

(a) in FIG. 10A shows an example where decoding of SAO information isperformed in one parallel. As shown by (a) in FIG. 10A, in the movingpicture decoding method in this embodiment, SAO_OFFSET, SAO_OFFSET_SIGN,and SAO_BAND_POSITION, that is, information items (parameters) includedin a bit stream BS are decoded in this order. It is to be noted that inFIG. 10A to FIG. 10C, a SAO offset value, a SAO offset sign, and SAOpixel value band position information are shown as SAO_OFFSET,SAO_OFFSET_SIGN, and SAO_BAND_POSITION, respectively.

Bypass arithmetic decoding is performed on, among the information items,the SAO_OFFSET_SIGN and the SAO_BAND_POSITION enclosed by thick framelines in FIG. 10A. Here, it is desirable to implement processing inparallel, because it is necessary to increase a processing speed whileimage resolution utilized is increased, and high-speed real timecommunication is widely used. However, because context adaptive binaryarithmetic coding is performed on at least part of the SAO_OFFSET, it isnecessary to sequentially read a symbol occurrence probability andperform an update process. For this reason, it is not possible toperform the arithmetic decoding of the SAO_OFFSET in parallel. In viewof this, as shown by (b) in FIG. 10A, parts on which bypass arithmeticdecoding is performed are decoded in parallel on a bit-by-bit basis. Inaddition, when bypass arithmetic decoding is performed in parallel,pre-calculation for bypass arithmetic decoding can be performedregardless of the internal state of the moving picture decodingapparatus 100, and thus upon obtaining information from the bit streamBS, the moving picture decoding apparatus 100 may start bypassarithmetic decoding even when context adaptive binary arithmeticdecoding is not completed. This makes higher-speed decoding possible.

FIG. 10B is a diagram for illustrating an exemplary sequence and anexemplary decoding order of parameters included in SAO information whichare used for performing the operation shown in FIG. 3. It is to be notedthat (a) and (b) in FIG. 10B correspond to (a) and (b) in FIG. 10A,respectively. Moreover, context adaptive binary arithmetic decoding issequentially performed on the SAO_OFFSET, and bypass arithmetic decodingcan be performed on the SAO_BAND_POSITION and the SAO_OFFSET_SIGN inparallel. However, because parts on which bypass arithmetic decoding isperformed precede and follow a part on which context adaptive binaryarithmetic decoding is performed, a portion on which parallel processingcan be performed is disrupted. Thus, the sequence of the parametersshown in FIG. 10A in this embodiment is more suitable for high-speedprocessing than the sequence of the parameters shown in FIG. 10B.However, the sequence of the parameters shown in FIG. 10B allows themoving picture decoding apparatus to recognize in advance a band offsetposition (SAO pixel value band position information), and thus there isan advantage of determining in advance a storage position inside amemory at which a SAO offset value is stored according to the SAO pixelvalue band position information. In contrast, in this embodiment, thestorage position is determined regardless of the band offset position(SAO pixel value band position information), and the SAO pixel valueband position information indicating the band offset position istransmitted to the loop filter 130 when SAO is applied. With this, it ispossible to successfully decode the parameters according to the order ofthe parameters shown in FIG. 10A.

It is to be noted that in the example shown in FIG. 10A, in the casewhere an i (where i is an integer greater than or equal to 2) number ofSAO_OFFSET is present even when context binary arithmetic coding isperformed on the whole or part of SAO_OFFSET, the i number of SAO_OFFSETis decoded in the order of being included in the bit stream BS. However,the present disclosure is not limited to this, a PREFIX partcollectively including only the parts of each SAO_OFFSET and a SUFFIXpart collectively including only the remaining parts of each SAO_OFFSETmay be decoded in order.

FIG. 10C is a diagram showing an exemplary sequence of parametersincluded in SAO information and an exemplary decoding order of theparameters when the i number of SAO_OFFSET each includes a PREFIX partand a SUFFIX part.

For instance, context adaptive binary arithmetic coding is performed ononly the first N number of bits of SAO_OFFSET, and bypass arithmeticcoding is performed on the remaining bits. In addition, as stated, the i(i=4 in a Non Patent Literature) number of SAO_OFFSET is present. Insuch a case, the bit stream BS includes: a PREFIX part(SAO_OFFSET_PREFIX) which collectively includes parts (the N number ofthe bits) on which context adaptive binary arithmetic coding isperformed and is shown by (a) in FIG. 10C; and a SUFFIX part(SAO_OFFSET_SUFFIX) which collectively includes parts on which bypassarithmetic coding is performed and is shown by (a) in FIG. 10C, thePREFIX part and the SUFFIX part being included in each of the i numberof SAO_OFFSET. In addition, the SUFFIX part follows the PREFIX part. Inthis embodiment, when such a bit stream BS is decoded, as shown by (b)in FIG. 10C, bypass arithmetic decoding is continuously performed notonly on SAO_OFFSET_SIGN and SAO_BAND_POSITION but also onSAO_OFFSET_SUFFIX, the SUFFIX part. With this, it is possible toincrease a parallel processing capability to achieve high-speeddecoding.

As described, the moving picture decoding apparatus and the movingpicture decoding method according to Embodiment 1 make it possible toefficiently decode, at high speed, the SAO information included in thebit stream.

Specifically, as described in Embodiment 1, it is possible to obtain agreater part on which parallel operation can be performed, by performingcontext adaptive binary arithmetic decoding on, among the multiple typesof the information included in the SAO information, predetermined typesof information, and continuously performing bypass arithmetic decodingon other multiple types of information, thereby performing efficientparallel processing, that is, high-speed decoding.

Moreover, it is possible to remove a determination process (e.g., stepSB02 in FIG. 3) by decoding relevant information (sao_band_position) ofband offset after sao_offset, thereby decoding an efficiently coded bitstream.

It is to be noted that although decoding applied to each of theparameters is switched between context adaptive binary arithmeticdecoding and bypass arithmetic decoding for each parameter in the abovedescription, the present disclosure is not limited to this. For example,as shown in FIG. 10C, an advantageous effect of reducing a certainamount of processing is expected by only switching decoding applied toeach of parts included in a parameter between context adaptive binaryarithmetic decoding and bypass arithmetic decoding for each part. Inthis case, not only the advantageous effect of this embodiment but alsoreduction of an internal memory can be achieved.

It is to be noted that as an exemplary way of selecting a binary string,a Huffman code may be derived from a mode number obtained based on anoccurrence frequency, a table may be generated from the code, and a partin which an occurrence probability is biased may be selected as a prefixpart. Determining the binary string in this manner makes it possible toincrease a parallel processing capability, and perform higher-speeddecoding.

As another way of selecting a binary string, a binary string may have afixed length. Here, SAO information is used for a loop filter process,which affects the image quality of an output image. A part on whichbypass arithmetic decoding is performed has directly something to dowith an amount of encoding in particular, and thus using the fixedlength when a moving picture coding apparatus performs selectionregardless of the amount of encoding allows the moving picture codingapparatus to select the SAO information according to the characteristicsof video. As a result, it is possible to provide a decoded image havinghigh image quality.

It is to be noted that although this embodiment has described the casewhere context adaptive binary arithmetic coding is performed on the atleast part of the SAO offset value (sao_offset), the parameter, thepresent disclosure is not limited to this. Even when bypass arithmeticcoding is performed on the whole of the parameter, by performing bypassarithmetic decoding in parallel using the order described in thisembodiment which is different from the conventional method, it ispossible to perform high-speed decoding. Moreover, it is possible toproduce an advantageous effect of removing a process of determiningwhether or not band offset is indicated, and to aim for reduction in aburden of processing.

Embodiment 2

A moving picture coding apparatus in this embodiment codes a movingpicture to generate a bit stream BS decoded by the moving picturedecoding apparatus 100 according to Embodiment 1.

FIG. 11 is a block diagram showing an exemplary configuration of amoving picture coding apparatus 200 according to Embodiment 2.

As shown in FIG. 11, the moving picture coding apparatus 200 includes asubtractor 205, a transform and quantization unit 210, an entropy codingunit 220, an inverse quantization and inverse transform unit 230, anadder 235, a loop filter 240, a memory 250, an intra prediction unit260, a motion detection unit 270, a motion compensation unit 280, and anintra/inter change switch 290.

The subtractor 205 calculates a difference between a prediction signaland an input signal representing an image, that is, a prediction error.

The transform and quantization unit 210 transforms a prediction error ina spatial domain to generate a transform coefficient in a frequencydomain. For example, the transform and quantization unit 210 performsdiscrete cosine transform (DCT) on the prediction error, to generate atransform coefficient. Furthermore, the transform and quantization unit210 quantizes the transform coefficient, to generate a quantizationcoefficient.

The entropy coding unit 220 performs variable length coding on thequantization coefficient, to generate a coded signal (bit stream).Moreover, the entropy coding unit 220 codes motion data (e.g., a motionvector) detected by the motion detection unit 270, and outputs the codedmotion data included in the coded signal. Furthermore, the entropycoding unit 220 performs variable length coding on SAO information usedby the loop filter 240, and include the SAO information on whichvariable length coding has been performed into the coded signal.

The inverse quantization and inverse transform unit 230 performs inversequantization on the quantization coefficient, to reconstruct a transformcoefficient. Moreover, the inverse quantization and inverse transformunit 230 performs inverse transform on the reconstructed transformcoefficient, to reconstruct a prediction error. It is to be noted thatbecause the reconstructed prediction error has lost information due tothe quantization, the reconstructed prediction error does not match theprediction error generated by the subtractor 205. To put it another way,the reconstructed prediction error includes a quantization error.

The adder 235 adds the reconstructed prediction error to the predictionsignal, to generate a local decoded image (provisionally decoded image).

The loop filter 240 performs a loop filter process on the generatedlocal decoded image. It is to be noted that the loop filter processincludes SAO. In other words, the loop filter 240 performs SAO on thelocal decoded image using SAO information, and outputs the SAOinformation to the entropy coding unit 220.

The memory 250 is a memory for storing reference images used for motioncompensation. Specifically, the memory 250 stores local decoded imageson which the loop filter process has been performed.

The intra prediction unit 260 performs intra prediction to generate aprediction signal (intra-prediction signal). Specifically, the intraprediction unit 260 performs intra prediction by referring to an imagearound a current block to be coded (input signal) in the local decodedimage generated by the adder 235, to generate an intra-predictionsignal.

The motion detection unit 270 detects motion data (e.g., a motionvector) between the input signal and a reference image stored in thememory 250.

The motion compensation unit 280 performs motion compensation based onthe detected motion data, to generate a prediction signal(inter-prediction signal).

The intra/inter change switch 290 selects either the intra-predictionsignal or the inter-prediction signal, and outputs the selected signalto the subtractor 205 and the adder 235 as the prediction signal.

The above configuration allows the moving picture coding apparatus 200according to Embodiment 2 to compression-code image data.

Here in Embodiment 2, the entropy coding unit 220 includes a SAOinformation coding unit that codes SAO information.

The following describes an overview of an arithmetic coding methodperformed by the SAO information coding unit in this embodiment. Unlikethe conventional arithmetic coding methods for SAO information, thearithmetic coding method performed by the SAO information coding unit inthis embodiment includes: performing context adaptive binary arithmeticcoding on a predetermined parameter included in SAO information; andcontinuously performing bypass arithmetic coding on parameters of othermultiple types included in the SAO information. With this, it ispossible to achieve efficient parallelization of processing, and codethe SAO information at high speed.

The overview of the arithmetic coding method in this embodiment has beendescribed above. The same method as the conventional arithmetic codingmethods may be used, unless otherwise explained.

Next, the flow of the arithmetic coding method for SAO information inthis embodiment is described.

FIG. 12 is a flow chart showing arithmetic coding by the SAO informationcoding unit according to Embodiment 2. First, the SAO information codingunit codes sao_type_idx (S501). It is to be noted that the sao_type_idxdoes not need to be the information per se shown in FIG. 1A. Forinstance, as long as the sao_type_idx is information for identifying SAOtype information such as a flag indicating that the same SAO typeinformation as the SAO type information of a left target region is to beused, the sao_type_idx is not limited to the information shown in FIG.1A. This embodiment is characterized by a coding order of subsequent bitstreams.

Next, when the sao_type_idx indicates that SAO is not to be performed(Sao off) (YES in S502), because it is no longer necessary to code SAOinformation, the SAO information coding unit terminates coding of SAOinformation. In contrast, when the sao_type_idx does not indicate Saooff (NO in S502), the SAO information coding unit codes a SAO offsetvalue (sao_offset) (S503). Here, context adaptive binary arithmeticcoding is performed on at least part of the sao_offset, and the at leastpart of the sao_offset is included in a bit stream by a predeterminedmethod (S503). It is to be noted that the SAO information coding unitrepeatedly performs the coding in step S503 until a predetermined numberof sao_offset is coded (during a period of NO in S504). When all ofsao_offset are coded (YES in S504), the SAO information coding unitdetermines whether or not the sao_type_idx indicates band offset (S505).When determining that the sao_type_idx does not indicate band offset (NOin S505), the SAO information coding unit terminates the coding of theSAO information. In contrast, when determining that the sao_type_idxindicates band offset (YES in S505), the SAO information coding unitdetermines whether or not the value of the already coded sao_offset iszero (S506).

Here, when determining that the value of the sao_offset is not zero (NOin S506), the SAO information coding unit codes a SAO offset signcorresponding to the sao_offset (S507). Bypass arithmetic coding isperformed on the SAO offset sign. It is to be noted that the details ofbypass arithmetic coding are the same as those of CABAC described inNPLs 1 to 3, and bypass arithmetic coding is processing comparable tobypass arithmetic decoding. In contrast, when determining that the valueof the sao_offset is zero (YES in S506), the SAO information coding unitskips coding. The SAO information coding unit repeats steps S506 andS507 for all values of sao_offset (S508), and codes SAO pixel value bandposition information (sao_band_position) (S509) when the processes forall the values of the sao_offset are terminated (YES in S508). Thisparameter is a parameter on which bypass arithmetic coding is performedas above. Then, the coding of the SAO information is terminated.

It is to be noted that parameters that are information coded in thesteps enclosed by double frame lines in FIG. 12 are parameters on whichbypass arithmetic coding is performed. In addition, because aprobability value is fixed in bypass arithmetic coding applied to theseparameters, it is possible to code the parameters in parallel.

It is to be noted that conventional bypass arithmetic coding can be usedfor bypass arithmetic coding. In addition, bypass arithmetic coding maybe arithmetic coding that does not require update of a probabilityvalue, and be different from arithmetic coding described in NPL 1 or 2.

It is to be noted that even the arithmetic coding method for SAOinformation in this embodiment makes it possible to achieve theefficient parallelization of processing as shown in FIG. 10A and FIG.10C described in Embodiment 1, and thus it is possible to performhigh-speed coding.

Here, a syntax for generating a bit stream in this embodiment isdescribed by comparison with a conventional example.

FIG. 13A is a table showing a syntax for generating a conventional bitstream shown in NPL 3.

In this bit stream, part on which bypass arithmetic coding is performedis divided by part on which context adaptive binary arithmetic coding isperformed. Further, a determination step of determining whether or notsao_type_idx indicates band offset coexists in processing of generatingthe bit stream. For this reason, it is difficult to perform thehigh-speed coding.

FIG. 13B is a table showing a syntax for generating a bit stream in thisembodiment.

In this bit stream, parameters of multiple types on which bypassarithmetic coding is performed concentrate at the latter part. Further,because the above determination step is arranged, it is easy to performthe high-speed coding.

It is to be noted that in this embodiment, because the SAO pixel valueband position information (sao_band_position) in the SAO information iscoded last, when the SAO offset value (sao_offset) is decoded, it isnecessary to consider a position at which the SAO offset value isstored, which increases a burden accordingly. However, an advantageouseffect produced by this embodiment more than makes up for a demeritcaused by the burden, and thus the moving picture coding methodaccording to this embodiment is meaningful.

FIG. 14 is a table showing a syntax for generating another bit stream inthis embodiment.

In this bit stream, a SAO offset value (sao_offset) is divided into aPREFIX part on which context adaptive binary arithmetic coding isperformed and a SUFFIX part on which bypass arithmetic coding isperformed. In this case, as shown in FIG. 10C, it is possible to performhigher-speed coding.

It is to be noted that although this embodiment has described the casewhere context adaptive binary arithmetic coding is performed on the atleast part of the SAO offset value (sao_offset), the parameter, thepresent disclosure is not limited to this. Even when bypass arithmeticcoding is performed on the whole of the parameter, by performing bypassarithmetic coding in parallel using the order described in thisembodiment which is different from the conventional method, it ispossible to perform the high-speed coding. Moreover, it is possible toproduce an advantageous effect of removing a process of determiningwhether or not band offset is indicated, and to aim for reduction in aburden of processing.

Although the moving picture coding method and the moving picturedecoding method according to aspects of the present disclosure have beendescribed based on this embodiment, the present disclosure is notlimited to this embodiment. Those skilled in the art will readilyappreciate that various modifications may be made in this embodiment andthat other embodiments may be obtained by arbitrarily combining thestructural elements of the embodiments. Accordingly, all suchmodifications and other embodiments are included in the aspects of thepresent disclosure.

FIG. 15A is a flow chart for a moving picture coding method in anotherembodiment.

This moving picture coding method is a moving picture coding method inwhich an input image is coded to generate a bit stream, and includesstep S11 and step S12. In step S11, context adaptive binary arithmeticcoding in which a variable probability value is used is performed onfirst information among multiple types of SAO information (parameters)used for sample adaptive offset (SAO) that is a process of assigning anoffset value to a pixel value of a pixel included in an image generatedby coding an input image. In step S12, bypass arithmetic coding in whicha fixed probability value is used is continuously performed on secondinformation and third information among the multiple types of the SAOinformation. As a result, the coded second and third information areplaced after the coded first information in a bit stream.

FIG. 15B is a block diagram showing a moving picture coding apparatus inthe other embodiment.

A moving picture coding apparatus 10 is a moving picture codingapparatus that codes an input image to generate a bit stream, andincludes a context adaptive binary arithmetic coding unit 11 and abypass arithmetic coding unit 12. The context adaptive binary arithmeticcoding unit 11 performs context adaptive binary arithmetic coding inwhich a variable probability value is used, on first information amongmultiple types of SAO information (parameters) used for sample adaptiveoffset (SAO) that is a process of assigning an offset value to a pixelvalue of a pixel included in an image generated by coding an inputimage. The bypass arithmetic coding unit 12 continuously performs bypassarithmetic coding in which a fixed probability value is used, on secondinformation and third information among the multiple types of the SAOinformation. As a result, the coded second and third information areplaced after the coded first information in the bit stream.

FIG. 15C is a flow chart for a moving picture decoding method in theother embodiment.

This moving picture decoding method is a moving picture decoding methodin which a coded image included in a bit stream is decoded, and includesstep S21 and step S22. In step S21, context adaptive binary arithmeticdecoding in which a variable probability value is used is performed onfirst information among multiple types of SAO information (parameters)that are included in a bit stream and used for sample adaptive offset(SAO) which is a process of assigning an offset value to a pixel valueof a pixel included in an image generated by decoding an coded image. Instep S22, bypass arithmetic decoding in which a fixed probability valueis used is continuously performed on second information and thirdinformation that are among the multiple types of the SAO information andlocated after the first information in the bit stream.

FIG. 15D is a block diagram showing a moving picture decoding apparatusin the other embodiment.

A moving picture decoding apparatus 20 is a moving picture decodingapparatus that decodes a coded image included in a bit stream, andincludes a context adaptive binary arithmetic decoding unit 21 and abypass arithmetic decoding unit 22. The context adaptive binaryarithmetic decoding unit 21 performs context adaptive binary arithmeticdecoding in which a variable probability value is used, on firstinformation among multiple types of SAO information (parameters) thatare included in the bit stream and used for sample adaptive offset (SAO)which is a process of assigning an offset value to a pixel value of apixel included in an image generated by decoding an coded image. Thebypass arithmetic decoding unit 22 continuously performs bypassarithmetic decoding in which a fixed probability value is used, onsecond information and third information that are among the multipletypes of the SAO information and located after the first information inthe bit stream.

Each of the structural elements in each of the above-describedembodiments may be configured in the form of an exclusive hardwareproduct, or may be realized by executing a software program suitable forthe structural element. Each of the structural elements may be realizedby means of a program executing unit, such as a CPU and a processor,reading and executing the software program recorded on a recordingmedium such as a hard disk and a semiconductor memory. Here, a softwareprogram for realizing the moving picture coding apparatus according toeach of the embodiments is a program causing a computer to execute thesteps shown in FIG. 15A. In addition, a software program for realizingthe moving picture decoding apparatus according to each of theembodiments is a program causing a computer to execute the steps shownin FIG. 15C.

To put it another way, the moving picture coding apparatus and themoving picture decoding apparatus include a control circuit (controlcircuitry) and a storage device (storage) that is electrically connectedto the control circuit (accessible from the control circuit). Thecontrol circuit includes at least one of an exclusive hardware productand a program executing unit. Furthermore, when the control circuitincludes the program executing unit, the storage device stores asoftware program executed by the program executing unit.

Embodiment 3

An independent computer system can easily perform processing describedin each of the embodiments by recording, in a recording medium, aprogram for implementing the structure of the moving picture codingmethod (image coding method) or the moving picture decoding method(image decoding method) according to each embodiment. The recordingmedium may be any as long as the program can be recorded thereon, suchas a magnetic disk, an optical disk, an optical magnetic disk, an ICcard, and a semiconductor memory.

Hereinafter, applications of the moving picture coding method (imagecoding method) and the moving picture decoding method (image decodingmethod) according to each of the embodiments, and a system using suchapplications will be described. The system features including an imagecoding apparatus using the image coding method, and an image coding anddecoding apparatus including an image decoding apparatus using the imagedecoding method. The other configurations of the system can beappropriately changed depending on a case.

FIG. 16 illustrates an overall configuration of a content providingsystem ex100 for implementing content distribution services. The areafor providing communication services is divided into cells of desiredsize, and base stations ex106 to ex110 which are fixed wireless stationsare placed in each of the cells.

The content providing system ex100 is connected to devices, such as acomputer ex111, a personal digital assistant (PDA) ex112, a cameraex113, a cellular phone ex114, and a game machine ex115, via an Internetex101, an Internet service provider ex102, a telephone network ex104, aswell as the base stations ex106 to ex110.

However, the configuration of the content providing system ex100 is notlimited to the configuration shown in FIG. 16, and a combination inwhich any of the elements are connected is acceptable. In addition, eachof the devices may be directly connected to the telephone network ex104,rather than via the base stations ex106 to ex110 which are the fixedwireless stations. Furthermore, the devices may be interconnected toeach other via a short distance wireless communication and others.

The camera ex113, such as a digital video camera, is capable ofcapturing moving images. A camera ex116, such as a digital video camera,is capable of capturing both still images and moving images.Furthermore, the cellular phone ex114 may be the one that meets any ofthe standards such as Global System for Mobile Communications (GSM),Code Division Multiple Access (CDMA), Wideband-Code Division MultipleAccess (W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access(HSPA). Alternatively, the cellular phone ex114 may be a PersonalHandyphone System (PHS).

In the content providing system ex100, a streaming server ex103 isconnected to the camera ex113 and others via the telephone network ex104and the base station ex109, which enables distribution of a live showand others. In such a distribution, a content (for example, video of amusic live show) captured by the user using the camera ex113 is coded(that is, functions as the image coding apparatus according to an aspectof the present disclosure) as described above in each of theembodiments, and the coded content is transmitted to the streamingserver ex103. On the other hand, the streaming server ex103 carries outstream distribution of the received content data to the clients upontheir requests. The clients include the computer ex111, the PDA ex112,the camera ex113, the cellular phone ex114, and the game machine ex115that are capable of decoding the above-mentioned coded data. Each of thedevices that have received the distributed data decodes and reproducesthe coded data (that is, functions as the image decoding apparatusaccording to an aspect of the present disclosure).

The captured data may be coded by the camera ex113 or the streamingserver ex103 that transmits the data, or the coding processes may beshared between the camera ex113 and the streaming server ex103.Similarly, the distributed data may be decoded by the clients or thestreaming server ex103, or the decoding processes may be shared betweenthe clients and the streaming server ex103. Furthermore, the data of thestill images and the moving images captured by not only the camera ex113but also the camera ex116 may be transmitted to the streaming serverex103 through the computer ex111. The coding processes may be performedby the camera ex116, the computer ex111, or the streaming server ex103,or shared among them.

Furthermore, generally, the computer ex111 and an LSI ex500 included ineach of the devices perform such encoding and decoding processes. TheLSI ex500 may be configured of a single chip or a plurality of chips.Software for encoding and decoding moving pictures may be integratedinto some type of a recording medium (such as a CD-ROM, a flexible disk,and a hard disk) that is readable by the computer ex111 and others, andthe encoding and decoding processes may be performed using the software.

Furthermore, when the cellular phone ex114 is equipped with a camera,the video data obtained by the camera may be transmitted. The video datais data coded by the LSI ex500 included in the cellular phone ex114.

Furthermore, the streaming server ex103 may be composed of servers andcomputers, and may decentralize data and process the decentralized data,record, or distribute data.

As described above, the clients can receive and reproduce the coded datain the content providing system ex100. In other words, the clients canreceive and decode information transmitted by the user, and reproducethe decoded data in real time in the content providing system ex100, sothat the user who does not have any particular right and equipment canimplement personal broadcasting.

Aside from the example of the content providing system ex100, at leastone of the moving picture coding apparatus (the image coding apparatus)and the moving picture decoding apparatus (the image decoding apparatus)described in each of the embodiments may be implemented in a digitalbroadcasting system ex200 illustrated in FIG. 17. More specifically, abroadcast station ex201 communicates or transmits, via radio waves to abroadcast satellite ex202, multiplexed data obtained by multiplexing theaudio data onto the video data. The video data is data coded by themoving picture coding method described in each of the embodiments (thatis, data coded by the image coding apparatus according to an aspect ofthe present disclosure). Upon receipt of the video data, the broadcastsatellite ex202 transmits radio waves for broadcasting. Then, a home-useantenna ex204 capable of receiving a satellite broadcast receives theradio waves. Next, a device such as a television (receiver) ex300 and aset top box (STB) ex217 decodes the received multiplexed data, andreproduces the decoded data (that is, functions as the image decodingapparatus according to an aspect of the present disclosure).

Furthermore, a reader/recorder ex218 that (i) reads and decodes themultiplexed data recorded on a recording media ex215, such as a DVD anda BD, or (ii) codes video signals in the recording medium ex215, and insome cases, writes data obtained by multiplexing an audio signal on thecoded data can include the moving picture decoding apparatus or themoving picture coding apparatus as shown in each of the embodiments. Inthis case, the reproduced video signals are displayed on the monitorex219, and another apparatus or system can reproduce the video signals,using the recording medium ex215 on which the multiplexed data isrecorded. Furthermore, it is also possible to implement the movingpicture decoding apparatus in the set top box ex217 connected to thecable ex203 for a cable television or the antenna ex204 for satelliteand/or terrestrial broadcasting, so as to display the video signals onthe monitor ex219 of the television ex300. The moving picture decodingapparatus may be included not in the set top box but in the televisionex300.

FIG. 18 illustrates the television (receiver) ex300 that uses the movingpicture coding method and the moving picture decoding method describedin each of Embodiments. The television ex300 includes: a tuner ex301that obtains or provides multiplexed data obtained by multiplexing theaudio data and the video data through the antenna ex204 or the cableex203, etc. that receives a broadcast; a modulation/demodulation unitex302 that demodulates the received multiplexed data or modulates datainto multiplexed data to be supplied outside; and amultiplexing/demultiplexing unit ex303 that demultiplexes the modulatedmultiplexed data into video data and audio data, or multiplexes thevideo data and audio data coded by the signal processing unit ex306 intodata.

The television ex300 further includes: a signal processing unit ex306including an audio signal processing unit ex304 and a video signalprocessing unit ex305 that decode audio data and video data and codeaudio data and video data, respectively (that function as the imagecoding apparatus and the image decoding apparatus, respectively,according to an aspect of the present disclosure); and an output unitex309 including a speaker ex307 that provides the decoded audio signal,and a display unit ex308 that displays the decoded video signal, such asa display. Furthermore, the television ex300 includes an interface unitex317 including an operation input unit ex312 that receives an input ofa user operation. Furthermore, the television ex300 includes a controlunit ex310 that controls overall each constituent element of thetelevision ex300, and a power supply circuit unit ex311 that suppliespower to each of the elements. Other than the operation input unitex312, the interface unit ex317 may include: a bridge ex313 that isconnected to an external device, such as the reader/recorder ex218; aslot unit ex314 for enabling attachment of the recording medium ex216,such as an SD card; a driver ex315 to be connected to an externalrecording medium, such as a hard disk; and a modem ex316 to be connectedto a telephone network. Here, the recording medium ex216 canelectrically record information using a non-volatile/volatilesemiconductor memory element for storage. The constituent elements ofthe television ex300 are connected to one another through a synchronousbus.

First, a configuration in which the television ex300 decodes themultiplexed data obtained from outside through the antenna ex204 andothers and reproduces the decoded data will be described. In thetelevision ex300, upon receipt of a user operation from a remotecontroller ex220 and others, the multiplexing/demultiplexing unit ex303demultiplexes the multiplexed data demodulated by themodulation/demodulation unit ex302, under control of the control unitex310 including a CPU. Furthermore, the audio signal processing unitex304 decodes the demultiplexed audio data, and the video signalprocessing unit ex305 decodes the demultiplexed video data, using thedecoding method described in each of the embodiments, in the televisionex300. The output unit ex309 provides the decoded video signal and audiosignal outside. When the output unit ex309 provides the video signal andthe audio signal, the signals may be temporarily stored in buffers ex318and ex319, and others so that the signals are reproduced insynchronization with each other. Furthermore, the television ex300 mayread the multiplexed data not through a broadcast and others but fromthe recording media ex215 and ex216, such as a magnetic disk, an opticaldisc, and an SD card. Next, a configuration in which the televisionex300 codes an audio signal and a video signal, and transmits the dataoutside or writes the data on a recording medium will be described. Inthe television ex300, upon receipt of a user operation from the remotecontroller ex220 and others, the audio signal processing unit ex304codes an audio signal, and the video signal processing unit ex305 codesa video signal, under control of the control unit ex310 using the codingmethod as described in each of the embodiments. Themultiplexing/demultiplexing unit ex303 multiplexes the coded videosignal and audio signal, and provides the resulting signal outside. Whenthe multiplexing/demultiplexing unit ex303 multiplexes the video signaland the audio signal, the signals may be temporarily stored in buffersex320 and ex321, and others so that the signals are reproduced insynchronization with each other. Here, the buffers ex318 to ex321 may beplural as illustrated, or at least one buffer may be shared in thetelevision ex300. Furthermore, data may be stored in a buffer other thanthe buffers ex318 to ex321 so that the system overflow and underflow maybe avoided between the modulation/demodulation unit ex302 and themultiplexing/demultiplexing unit ex303, for example.

Furthermore, the television ex300 may include a configuration forreceiving an AV input from a microphone or a camera other than theconfiguration for obtaining audio and video data from a broadcast or arecording medium, and may code the obtained data. Although thetelevision ex300 can code, multiplex, and provide outside data in thedescription, it may be not capable of performing all the processes butcapable of only one of receiving, decoding, and providing outside data.

Furthermore, when the reader/recorder ex218 reads or writes themultiplexed data from or in a recording medium, one of the televisionex300 and the reader/recorder ex218 may decode or code the multiplexeddata, and the television ex300 and the reader/recorder ex218 may sharethe decoding or encoding.

As an example, FIG. 19 illustrates a configuration of an informationreproducing/recording unit ex400 when data is read or written from or onan optical disk. The information reproducing/recording unit ex400includes constituent elements ex401 to ex407 to be describedhereinafter. The optical head ex401 irradiates a laser spot on arecording surface of the recording medium ex215 that is an optical discto write information, and detects reflected light from the recordingsurface of the recording medium ex215 to read the information. Themodulation recording unit ex402 electrically drives a semiconductorlaser included in the optical head ex401, and modulates the laser lightaccording to recorded data. The reproduction demodulating unit ex403amplifies a reproduction signal obtained by electrically detecting thereflected light from the recording surface using a photo detectorincluded in the optical head ex401, and demodulates the reproductionsignal by separating a signal component recorded on the recording mediumex215 to reproduce the necessary information. The buffer ex404temporarily holds the information to be recorded on the recording mediumex215 and the information reproduced from the recording medium ex215. Adisk motor ex405 rotates the recording medium ex215. A servo controlunit ex406 moves the optical head ex401 to a predetermined informationtrack while controlling the rotation drive of the disk motor ex405 so asto follow the laser spot. The system control unit ex407 controls overallthe information reproducing/recording unit ex400. The reading andwriting processes can be implemented by the system control unit ex407using various information stored in the buffer ex404 and generating andadding new information as necessary, and by the modulation recordingunit ex402, the reproduction demodulating unit ex403, and the servocontrol unit ex406 that record and reproduce information through theoptical head ex401 while being operated in a coordinated manner. Thesystem control unit ex407 includes, for example, a microprocessor, andexecutes processing by causing a computer to execute a program for readand write.

Although the optical head ex401 irradiates a laser spot in thedescription, it may perform high-density recording using near fieldlight.

FIG. 20 illustrates the recording medium ex215 that is the optical disk.On the recording surface of the recording medium ex215, guide groovesare spirally formed, and an information track ex230 records, in advance,address information indicating an absolute position on the diskaccording to change in a shape of the guide grooves. The addressinformation includes information for determining positions of recordingblocks ex231 that are a unit for recording data. An apparatus thatrecords and reproduces data reproduces the information track ex230 andreads the address information so as to determine the positions of therecording blocks. Furthermore, the recording medium ex215 includes adata recording area ex233, an inner circumference area ex232, and anouter circumference area ex234. The data recording area ex233 is an areafor use in recording the user data. The inner circumference area ex232and the outer circumference area ex234 that are inside and outside ofthe data recording area ex233, respectively are for specific use exceptfor recording the user data. The information reproducing/recording unit400 reads and writes coded audio data, coded video data, or multiplexeddata obtained by multiplexing the coded audio data and the coded videodata, from and on the data recording area ex233 of the recording mediumex215.

Although an optical disc having a layer, such as a DVD and a BD isdescribed as an example in the description, the optical disc is notlimited to such, and may be an optical disc having a multilayerstructure and capable of being recorded on a part other than thesurface. Furthermore, the optical disc may have a structure formultidimensional recording/reproduction, such as recording ofinformation using light of colors with different wavelengths in the sameportion of the optical disc and recording information having differentlayers from various angles.

Furthermore, the car ex210 having the antenna ex205 can receive datafrom the satellite ex202 and others, and reproduce video on the displaydevice such as the car navigation system ex211 set in the car ex210, ina digital broadcasting system ex200. Here, a configuration of the carnavigation system ex211 will be a configuration, for example, includinga GPS receiving unit from the configuration illustrated in FIG. 18. Thesame will be true for the configuration of the computer ex111, thecellular phone ex114, and others.

FIG. 21A illustrates the cellular phone ex114 that uses the movingpicture coding method or the moving picture decoding method described inthe embodiments. The cellular phone ex114 includes: an antenna ex350 fortransmitting and receiving radio waves through the base station ex110; acamera unit ex365 capable of capturing moving and still images; and adisplay unit ex358 such as a liquid crystal display for displaying thedata such as decoded video captured by the camera unit ex365 or receivedby the antenna ex350. The cellular phone ex114 further includes: a mainbody unit including a set of operation keys ex366; an audio output unitex357 such as a speaker for output of audio; an audio input unit ex356such as a microphone for input of audio; a memory unit ex367 for storingcaptured video or still pictures, recorded audio, coded or decoded dataof the received video, the still images, e-mails, or others; and a slotunit ex364 that is an interface unit for a recording medium that storesdata in the same manner as the memory unit ex367.

Next, an example of a configuration of the cellular phone ex114 will bedescribed with reference to FIG. 21B. In the cellular phone ex114, amain control unit ex360 designed to control overall each unit of themain body including the display unit ex358 as well as the operation keysex366 is connected mutually, via a synchronous bus ex370, to a powersupply circuit unit ex361, an operation input control unit ex362, avideo signal processing unit ex355, a camera interface unit ex363, aliquid crystal display (LCD) control unit ex359, amodulation/demodulation unit ex352, a multiplexing/demultiplexing unitex353, an audio signal processing unit ex354, the slot unit ex364, andthe memory unit ex367.

When a call-end key or a power key is turned ON by a user's operation,the power supply circuit unit ex361 supplies the respective units withpower from a battery pack so as to activate the cell phone ex114.

In the cellular phone ex114, the audio signal processing unit ex354converts the audio signals collected by the audio input unit ex356 invoice conversation mode into digital audio signals under the control ofthe main control unit ex360 including a CPU, ROM, and RAM. Then, themodulation/demodulation unit ex352 performs spread spectrum processingon the digital audio signals, and the transmitting and receiving unitex351 performs digital-to-analog conversion and frequency conversion onthe data, so as to transmit the resulting data via the antenna ex350.Then, the modulation/demodulation unit ex352 performs inverse spreadspectrum processing on the data, and the audio signal processing unitex354 converts it into analog audio signals, so as to output them viathe audio output unit ex357.

Furthermore, when an e-mail in data communication mode is transmitted,text data of the e-mail inputted by operating the operation keys ex366and others of the main body is sent out to the main control unit ex360via the operation input control unit ex362. The main control unit ex360causes the modulation/demodulation unit ex352 to perform spread spectrumprocessing on the text data, and the transmitting and receiving unitex351 performs the digital-to-analog conversion and the frequencyconversion on the resulting data to transmit the data to the basestation ex110 via the antenna ex350. When an e-mail is received,processing that is approximately inverse to the processing fortransmitting an e-mail is performed on the received data, and theresulting data is provided to the display unit ex358.

When video, still images, or video and audio are transmitted in datacommunication mode, the video signal processing unit ex355 compressesand codes video signals supplied from the camera unit ex365 using themoving picture coding method shown in each of the embodiments (that is,functions as the image coding apparatus according to an aspect of thepresent disclosure), and transmits the coded video data to themultiplexing/demultiplexing unit ex353. In contrast, during when thecamera unit ex365 captures video, still images, and others, the audiosignal processing unit ex354 codes audio signals collected by the audioinput unit ex356, and transmits the coded audio data to themultiplexing/demultiplexing unit ex353.

The multiplexing/demultiplexing unit ex353 multiplexes the coded videodata supplied from the video signal processing unit ex355 and the codedaudio data supplied from the audio signal processing unit ex354, using apredetermined method. Then, the modulation/demodulation circuit unitex352 performs spread spectrum processing on the multiplexed data, andthe transmitting and receiving unit ex351 performs digital-to-analogconversion and frequency conversion on the data so as to transmit theresulting data via the antenna ex350.

When receiving data of a video file which is linked to a Web page andothers in data communication mode or when receiving an e-mail with videoand/or audio attached, in order to decode the multiplexed data receivedvia the antenna ex350, the multiplexing/demultiplexing unit ex353demultiplexes the multiplexed data into a video data bit stream and anaudio data bit stream, and supplies the video signal processing unitex355 with the coded video data and the audio signal processing unitex354 with the coded audio data, through the synchronous bus ex370. Thevideo signal processing unit ex355 decodes the video signal using amoving picture decoding method corresponding to the coding method shownin each of the embodiments (that is, functions as the image decodingapparatus according to an aspect of the present disclosure), and thenthe display unit ex358 displays, for instance, the video and stillimages included in the video file linked to the Web page via the LCDcontrol unit ex359. Furthermore, the audio signal processing unit ex354decodes the audio signal, and the audio output unit ex357 provides theaudio.

Furthermore, similarly to the television ex300, a terminal such as thecellular phone ex114 probably have three types of implementationconfigurations including not only (i) a transmitting and receivingterminal including both a coding apparatus and a decoding apparatus, butalso (ii) a transmitting terminal including only a coding apparatus and(iii) a receiving terminal including only a decoding apparatus. Althoughthe digital broadcasting system ex200 receives and transmits themultiplexed data obtained by multiplexing audio data onto video data inthe description, the multiplexed data may be data obtained bymultiplexing not audio data but character data related to video ontovideo data, and may be not multiplexed data but video data itself.

As such, the moving picture coding method or the moving picture decodingmethod in each of the embodiments can be used in any of the devices andsystems described above. Thus, the advantages described in each of theembodiment can be obtained.

Furthermore, various modifications and revisions can be made in any ofthe embodiments in the present disclosure.

Embodiment 4

Video data can be generated by switching, as necessary, between (i) themoving picture coding method or the moving picture coding apparatusshown in each of Embodiments and (ii) a moving picture coding method ora moving picture coding apparatus in conformity with a differentstandard, such as MPEG-2, MPEG4-AVC, and VC-1.

Here, when a plurality of video data that conforms to the differentstandards is generated and is then decoded, the decoding methods need tobe selected to conform to the different standards. However, since towhich standard each of the plurality of the video data to be decodedconforms cannot be detected, there is a problem that an appropriatedecoding method cannot be selected.

In order to solve the problem, multiplexed data obtained by multiplexingaudio data and others onto video data has a structure includingidentification information indicating to which standard the video dataconforms. The specific structure of the multiplexed data including thevideo data generated in the moving picture coding method or by themoving picture coding apparatus shown in each of Embodiments will behereinafter described. The multiplexed data is a digital stream in theMPEG-2 Transport Stream format.

FIG. 22 is a diagram showing a structure of multiplexed data. Asillustrated in FIG. 22, the multiplexed data can be obtained bymultiplexing at least one of a video stream, an audio stream, apresentation graphics stream (PG), and an interactive graphics stream.The video stream represents primary video and secondary video of amovie, the audio stream (IG) represents a primary audio part and asecondary audio part to be mixed with the primary audio part, and thepresentation graphics stream represents subtitles of a movie. Here, theprimary video is normal video to be displayed on a screen, and thesecondary video is video to be displayed on a smaller window in the mainvideo. Furthermore, the interactive graphics stream represents aninteractive screen to be generated by arranging the GUI components on ascreen. The video stream is coded in the moving picture coding method orby the moving picture coding apparatus shown in each of the embodiments,or in a moving picture coding method or by a moving picture codingapparatus in conformity with a conventional standard, such as MPEG-2,MPEG4-AVC, and VC-1. The audio stream is coded in accordance with astandard, such as Dolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, andlinear PCM.

Each stream included in the multiplexed data is identified by PID. Forexample, 0x1011 is allocated to the video stream to be used for video ofa movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to0x121F are allocated to the presentation graphics streams, 0x1400 to0x141F are allocated to the interactive graphics streams, 0x1B00 to0x1B1F are allocated to the video streams to be used for secondary videoof the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams tobe used for the secondary video to be mixed with the primary audio.

FIG. 23 schematically illustrates how data is multiplexed. First, avideo stream ex235 composed of video frames and an audio stream ex238composed of audio frames are transformed into a stream of PES packetsex236 and a stream of PES packets ex239, and further into TS packetsex237 and TS packets ex240, respectively. Similarly, data of apresentation graphics stream ex241 and data of an interactive graphicsstream ex244 are transformed into a stream of PES packets ex242 and astream of PES packets ex245, and further into TS packets ex243 and TSpackets ex246, respectively. These TS packets are multiplexed into astream to obtain multiplexed data ex247.

FIG. 24 illustrates how a video stream is stored in a stream of PESpackets in more detail. The first bar in FIG. 24 shows a video framestream in a video stream. The second bar shows the stream of PESpackets. As indicated by arrows denoted as yy1, yy2, yy3, and yy4 inFIG. 24, the video stream is divided into pictures as I-pictures,B-pictures, and P-pictures each of which is a video presentation unit,and the pictures are stored in a payload of each of the PES packets.Each of the PES packets has a PES header, and the PES header stores aPresentation Time-Stamp (PTS) indicating a display time of the picture,and a Decoding Time-Stamp (DTS) indicating a decoding time of thepicture.

FIG. 25 illustrates a format of TS packets to be finally written on themultiplexed data. Each of the TS packets is a 188-byte fixed lengthpacket including a 4-byte TS header having information, such as a PIDfor identifying a stream and a 184-byte TS payload for storing data. ThePES packets are divided, and stored in the TS payloads. When a BD ROM isused, each of the TS packets is given a 4-byte TP_Extra_Header, thusresulting in 192-byte source packets. The source packets are written onthe multiplexed data. The TP_Extra_Header stores information such as anArrival_Time_Stamp (ATS). The ATS shows a transfer start time at whicheach of the TS packets is to be transferred to a PID filter. The sourcepackets are arranged in the multiplexed data as shown at the bottom ofFIG. 25. The numbers incrementing from the head of the multiplexed dataare called source packet numbers (SPNs).

Each of the TS packets included in the multiplexed data includes notonly streams of audio, video, subtitles and others, but also a ProgramAssociation Table (PAT), a Program Map Table (PMT), and a Program ClockReference (PCR). The PAT shows what a PID in a PMT used in themultiplexed data indicates, and a PID of the PAT itself is registered aszero. The PMT stores PIDs of the streams of video, audio, subtitles andothers included in the multiplexed data, and attribute information ofthe streams corresponding to the PIDs. The PMT also has variousdescriptors relating to the multiplexed data. The descriptors haveinformation such as copy control information showing whether copying ofthe multiplexed data is permitted or not. The PCR stores STC timeinformation corresponding to an ATS showing when the PCR packet istransferred to a decoder, in order to achieve synchronization between anArrival Time Clock (ATC) that is a time axis of ATSs, and an System TimeClock (STC) that is a time axis of PTSs and DTSs.

FIG. 26 illustrates the data structure of the PMT in detail. A PMTheader is disposed at the top of the PMT. The PMT header describes thelength of data included in the PMT and others. A plurality ofdescriptors relating to the multiplexed data is disposed after the PMTheader. Information such as the copy control information is described inthe descriptors. After the descriptors, a plurality of pieces of streaminformation relating to the streams included in the multiplexed data isdisposed. Each piece of stream information includes stream descriptorseach describing information, such as a stream type for identifying acompression codec of a stream, a stream PID, and stream attributeinformation (such as a frame rate or an aspect ratio). The streamdescriptors are equal in number to the number of streams in themultiplexed data.

When the multiplexed data is recorded on a recording medium and others,it is recorded together with multiplexed data information files.

Each of the multiplexed data information files is management informationof the multiplexed data as shown in FIG. 27. The multiplexed datainformation files are in one to one correspondence with the multiplexeddata, and each of the files includes multiplexed data information,stream attribute information, and an entry map.

As illustrated in FIG. 27, the multiplexed data includes a system rate,a reproduction start time, and a reproduction end time. The system rateindicates the maximum transfer rate at which a system target decoder tobe described later transfers the multiplexed data to a PID filter. Theintervals of the ATSs included in the multiplexed data are set to nothigher than a system rate. The reproduction start time indicates a PTSin a video frame at the head of the multiplexed data. An interval of oneframe is added to a PTS in a video frame at the end of the multiplexeddata, and the PTS is set to the reproduction end time.

As shown in FIG. 28, a piece of attribute information is registered inthe stream attribute information, for each PID of each stream includedin the multiplexed data. Each piece of attribute information hasdifferent information depending on whether the corresponding stream is avideo stream, an audio stream, a presentation graphics stream, or aninteractive graphics stream. Each piece of video stream attributeinformation carries information including what kind of compression codecis used for compressing the video stream, and the resolution, aspectratio and frame rate of the pieces of picture data that is included inthe video stream. Each piece of audio stream attribute informationcarries information including what kind of compression codec is used forcompressing the audio stream, how many channels are included in theaudio stream, which language the audio stream supports, and how high thesampling frequency is. The video stream attribute information and theaudio stream attribute information are used for initialization of adecoder before the player plays back the information.

In this embodiment, the multiplexed data to be used is of a stream typeincluded in the PMT. Furthermore, when the multiplexed data is recordedon a recording medium, the video stream attribute information includedin the multiplexed data information is used. More specifically, themoving picture coding method or the moving picture coding apparatusdescribed in each of the embodiments includes a step or a unit forallocating unique information indicating video data generated by themoving picture coding method or the moving picture coding apparatus ineach of the embodiments, to the stream type included in the PMT or thevideo stream attribute information. With the structure, the video datagenerated by the moving picture coding method or the moving picturecoding apparatus described in each of the embodiments can bedistinguished from video data that conforms to another standard.

Furthermore, FIG. 29 illustrates steps of the moving picture decodingmethod according to this embodiment. In Step exS100, the stream typeincluded in the PMT or the video stream attribute information isobtained from the multiplexed data. Next, in Step exS101, it isdetermined whether or not the stream type or the video stream attributeinformation indicates that the multiplexed data is generated by themoving picture coding method or the moving picture coding apparatus ineach of the embodiments. When it is determined that the stream type orthe video stream attribute information indicates that the multiplexeddata is generated by the moving picture coding method or the movingpicture coding apparatus in each of the embodiments, in Step exS102, thestream type or the video stream attribute information is decoded by themoving picture decoding method in each of the embodiments. Furthermore,when the stream type or the video stream attribute information indicatesconformance to the conventional standards, such as MPEG-2, MPEG4-AVC,and VC-1, in Step exS103, the stream type or the video stream attributeinformation is decoded by a moving picture decoding method in conformitywith the conventional standards.

As such, allocating a new unique value to the stream type or the videostream attribute information enables determination whether or not themoving picture decoding method or the moving picture decoding apparatusthat is described in each of the embodiments can perform decoding. Evenupon an input of multiplexed data that conforms to a different standard,an appropriate decoding method or apparatus can be selected. Thus, itbecomes possible to decode information without any error. Furthermore,the moving picture coding method or apparatus, or the moving picturedecoding method or apparatus in this embodiment can be used in thedevices and systems described above.

Embodiment 5

Each of the moving picture coding method, the moving picture codingapparatus, the moving picture decoding method, and the moving picturedecoding apparatus in each of the embodiments is typically achieved inthe form of an integrated circuit or a Large Scale Integrated (LSI)circuit. As an example of the LSI, FIG. 30 illustrates a configurationof the LSI ex500 that is made into one chip. The LSI ex500 includeselements ex501, ex502, ex503, ex504, ex505, ex506, ex507, ex508, andex509 to be described below, and the elements are connected to eachother through a bus ex510. The power supply circuit unit ex505 isactivated by supplying each of the elements with power when the powersupply circuit unit ex505 is turned on.

For example, when coding is performed, the LSI ex500 receives an AVsignal from a microphone ex117, a camera ex113, and others through an AVIO ex509 under control of a control unit ex501 including a CPU ex502, amemory controller ex503, a stream controller ex504, and a drivingfrequency control unit ex512. The received AV signal is temporarilystored in an external memory ex511, such as an SDRAM. Under control ofthe control unit ex501, the stored data is segmented into data portionsaccording to the processing amount and speed to be transmitted to asignal processing unit ex507. Then, the signal processing unit ex507codes an audio signal and/or a video signal. Here, the coding of thevideo signal is the coding described in each of the embodiments.Furthermore, the signal processing unit ex507 sometimes multiplexes thecoded audio data and the coded video data, and a stream IO ex506provides the multiplexed data outside. The provided multiplexed data istransmitted to the base station ex107, or written on the recording mediaex215. When data sets are multiplexed, the data sets should betemporarily stored in the buffer ex508 so that the data sets aresynchronized with each other.

Although the memory ex511 is an element outside the LSI ex500, it may beincluded in the LSI ex500. The buffer ex508 is not limited to onebuffer, but may be composed of buffers. Furthermore, the LSI ex500 maybe made into one chip or a plurality of chips.

Furthermore, although the control unit ex501 includes the CPU ex502, thememory controller ex503, the stream controller ex504, the drivingfrequency control unit ex512, the configuration of the control unitex501 is not limited to such. For example, the signal processing unitex507 may further include a CPU. Inclusion of another CPU in the signalprocessing unit ex507 can improve the processing speed. Furthermore, asanother example, the CPU ex502 may include the signal processing unitex507, or an audio signal processing unit that is a part of the signalprocessing unit ex507. In such a case, the control unit ex501 includesthe signal processing unit ex507 or the CPU ex502 including a part ofthe signal processing unit ex507.

The name used here is LSI, but it may also be called IC, system LSI,super LSI, or ultra LSI depending on the degree of integration.

Moreover, ways to achieve integration are not limited to the LSI, and aspecial circuit or a general purpose processor and so forth can alsoachieve the integration. Field Programmable Gate Array (FPGA) that canbe programmed after manufacturing LSIs or a reconfigurable processorthat allows re-configuration of the connection or configuration of anLSI can be used for the same purpose. Such a programmable logic devicecan typically execute the moving picture coding method or the movingpicture decoding method shown in each of the embodiments, by loading orreading, from a memory or the like, a program included in software orfirmware.

In the future, with advancement in semiconductor technology, a brand-newtechnology may replace LSI. The functional blocks can be integratedusing such a technology. The possibility is that the present disclosureis applied to biotechnology.

Embodiment 6

When video data generated by the moving picture coding method or by themoving picture coding apparatus described in each of the embodiments isdecoded, compared to the case of decoding video data that conforms to aconventional standard, such as MPEG-2, MPEG4-AVC, and VC-1, thecomputing amount probably increases. Thus, the LSI ex500 needs to be setto a driving frequency higher than that of the CPU ex502 to be used whenvideo data in conformity with the conventional standard is decoded.However, when the driving frequency is set higher, there is a problemthat the power consumption increases.

In order to solve the problem, the moving picture decoding apparatus,such as the television ex300 and the LSI ex500 is configured todetermine to which standard the video data conforms, and switch betweenthe driving frequencies according to the determined standard. FIG. 31illustrates a configuration ex800 in this embodiment. A drivingfrequency switching unit ex803 sets a driving frequency to a higherdriving frequency when video data is generated by the moving picturecoding method or the moving picture coding apparatus described in eachof the embodiments. Then, the driving frequency switching unit ex803instructs a decoding processing unit ex801 that executes the movingpicture decoding method described in each of the embodiments to decodethe video data. When the video data conforms to the conventionalstandard, the driving frequency switching unit ex803 sets a drivingfrequency to a lower driving frequency than that of the video datagenerated by the moving picture coding method or the moving picturecoding apparatus described in each of the embodiments. Then, the drivingfrequency switching unit ex803 instructs the decoding processing unitex802 that conforms to the conventional standard to decode the videodata.

More specifically, the driving frequency switching unit ex803 includesthe CPU ex502 and the driving frequency control unit ex512 in FIG. 30.Here, each of the decoding processing unit ex801 that executes themoving picture decoding method described in each of the embodiments andthe decoding processing unit ex802 that conforms to the conventionalstandard corresponds to the signal processing unit ex503 in FIG. 30. TheCPU ex502 determines to which standard the video data conforms. Then,the driving frequency control unit ex512 determines a driving frequencybased on a signal from the CPU ex502. Furthermore, the signal processingunit ex507 decodes the video data based on a signal from the CPU ex502.For example, the identification information described in Embodiment 4 isprobably used for identifying the video data. The identificationinformation is not limited to the one described in Embodiment 4 but maybe any information as long as the information indicates to whichstandard the video data conforms. For example, when which standard videodata conforms to can be determined based on an external signal fordetermining that the video data is used for a television or a disk,etc., the determination may be made based on such an external signal.Furthermore, the CPU ex503 selects a driving frequency based on, forexample, a look-up table in which the standards of the video data areassociated with the driving frequencies as shown in FIG. 33. The drivingfrequency can be selected by storing the look-up table in the bufferex508 and an internal memory of an LSI, and with reference to thelook-up table by the CPU ex502.

FIG. 32 illustrates steps for executing a method in this embodiment.First, in Step exS200, the signal processing unit ex507 obtainsidentification information from the multiplexed data. Next, in StepexS201, the CPU ex502 determines whether or not the video data isgenerated based on the identification information by the coding methodand the coding apparatus described in each of the embodiments. When thevideo data is generated by the coding method or the coding apparatusdescribed in each of the embodiments, in Step exS202, the CPU ex502transmits a signal for setting the driving frequency to a higher drivingfrequency to the driving frequency control unit ex512. Then, the drivingfrequency control unit ex512 sets the driving frequency to the higherdriving frequency. On the other hand, when the identificationinformation indicates that the video data conforms to the conventionalstandard, such as MPEG-2, MPEG4-AVC, and VC-1, in Step exS203, the CPUex502 transmits a signal for setting the driving frequency to a lowerdriving frequency to the driving frequency control unit ex512. Then, thedriving frequency control unit ex512 sets the driving frequency to thelower driving frequency than that in the case where the video data isgenerated by the coding method or the coding apparatus described in eachof the embodiments.

Furthermore, along with the switching of the driving frequencies, thepower conservation effect can be improved by changing the voltage to beapplied to the LSI ex500 or an apparatus including the LSI ex500. Forexample, when the driving frequency is set lower, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set to a voltage lower than that in the case where the drivingfrequency is set higher.

Furthermore, when the computing amount for decoding is larger, thedriving frequency may be set higher, and when the computing amount fordecoding is smaller, the driving frequency may be set lower as themethod for setting the driving frequency. Thus, the setting method isnot limited to the ones described above. For example, when the computingamount for decoding video data in conformity with MPEG4-AVC is largerthan the computing amount for decoding video data generated by themoving picture coding method or the moving picture coding apparatusdescribed in each of the embodiments, the driving frequency is probablyset in reverse order to the setting described above.

Furthermore, the method for setting the driving frequency is not limitedto the method for setting the driving frequency lower. For example, whenthe identification information indicates that the video data isgenerated by the moving picture coding method or the moving picturecoding apparatus described in each of the embodiments, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set higher. When the identification information indicates thatthe video data conforms to the conventional standard, such as MPEG-2,MPEG4-AVC, and VC-1, the voltage to be applied to the LSI ex500 or theapparatus including the LSI ex500 is probably set lower. As anotherexample, when the identification information indicates that the videodata is generated by the moving picture coding method or the videocoding apparatus described in each of the embodiments, the driving ofthe CPU ex502 does not probably have to be suspended. When theidentification information indicates that the video data conforms to theconventional standard, such as MPEG-2, MPEG4-AVC, and VC-1, the drivingof the CPU ex502 is probably suspended at a given time because the CPUex502 has extra processing capacity. Even when the identificationinformation indicates that the video data is generated by the movingpicture coding method or the moving picture coding apparatus describedin each of the embodiments, in the case where the CPU ex502 has extraprocessing capacity, the driving of the CPU ex502 is probably suspendedat a given time. In such a case, the suspending time is probably setshorter than that in the case where when the identification informationindicates that the video data conforms to the conventional standard,such as MPEG-2, MPEG4-AVC, and VC-1.

Accordingly, the power conservation effect can be improved by switchingbetween the driving frequencies in accordance with the standard to whichthe video data conforms. Furthermore, when the LSI ex500 or theapparatus including the LSI ex500 is driven using a battery, the batterylife can be extended with the power conservation effect.

Embodiment 7

There are cases where a plurality of video data that conforms todifferent standards, is provided to the devices and systems, such as atelevision and a cellular phone. In order to enable decoding theplurality of video data that conforms to the different standards, thesignal processing unit ex507 of the LSI ex500 needs to conform to thedifferent standards. However, the problems of increase in the scale ofthe circuit of the LSI ex500 and increase in the cost arise with theindividual use of the signal processing units ex507 that conform to therespective standards.

In order to solve the problems, what is conceived is a configuration inwhich the decoding processing unit for implementing the moving picturedecoding method described in each of the embodiments and the decodingprocessing unit that conforms to the conventional standard, such asMPEG-2, MPEG4-AVC, and VC-1 are partly shared. ex900 in FIG. 34A showsan example of the configuration. For example, the moving picturedecoding method described in each of the embodiments and the movingpicture decoding method that conforms to MPEG4-AVC have, partly incommon, the details of processing, such as entropy coding, inversequantization, deblocking filtering, and motion compensation. The detailsof processing to be shared probably include use of a decoding processingunit ex902 that conforms to MPEG4-AVC. In contrast, a dedicated decodingprocessing unit ex901 is probably used for other processing that doesnot conform to MPEG4-AVC and is unique to an aspect of the presentdisclosure. The decoding processing unit for implementing the movingpicture decoding method described in each of the embodiments may beshared for the processing to be shared, and a dedicated decodingprocessing unit may be used for processing unique to that of MPEG4-AVC.

Furthermore, ex1000 in FIG. 34B shows another example in that processingis partly shared. This example uses a configuration including adedicated decoding processing unit ex1001 that supports the processingunique to an aspect of the present disclosure, a dedicated decodingprocessing unit ex1002 that supports the processing unique to anotherconventional standard, and a decoding processing unit ex1003 thatsupports processing to be shared between the moving picture decodingmethod according to the aspect of the present disclosure and theconventional moving picture decoding method. Here, the dedicateddecoding processing units ex1001 and ex1002 are not necessarilyspecialized for the processing of the aspect of the present disclosureand the processing of the conventional standard, respectively, and maybe the ones capable of implementing general processing. Furthermore, theconfiguration of this embodiment can be implemented by the LSI ex500.

As such, reducing the scale of the circuit of an LSI and reducing thecost are possible by sharing the decoding processing unit for theprocessing to be shared between the moving picture decoding methodaccording to the aspect of the present disclosure and the moving picturedecoding method in conformity with the conventional standard.

Although only some exemplary embodiments have been described above, thescope of the Claims of the present application is not limited to theseembodiments. Those skilled in the art will readily appreciate thatvarious modifications may be made in these exemplary embodiments andthat other embodiments may be obtained by arbitrarily combining thestructural elements of the embodiments without materially departing fromthe novel teachings and advantages of the subject matter recited in theappended Claims. Accordingly, all such modifications and otherembodiments are included in the present disclosure.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to, for example, televisionreceivers, digital video recorders, car navigation systems, cellularphones, digital cameras, digital video cameras, and so on.

The invention claimed is:
 1. A moving picture coding method for codingan input image to generate a bit stream, the method comprising:performing context adaptive binary arithmetic coding in which a variableprobability value is used on, from among multiple types of sampleadaptive offset (SAO) information used for SAO that is a process ofassigning an offset value to a pixel value of a pixel included in animage generated by coding the input image, part of sao_type_idxindicating that the SAO is not to be performed; and continuouslyperforming bypass arithmetic coding in which a fixed probability valueis used on, from among the multiple types of the SAO information, (i)sao_band_position indicating a range of pixel values to which the SAO isapplied and (ii) sao_offset_sign indicating whether the offset value ispositive or negative, wherein, in the bitstream, the codedsao_band_position and the coded sao_offset_sign are placed after thecoded sao_type_idx, and wherein a variable probability is not used inthe bypass arithmetic coding.
 2. The moving picture coding methodaccording to claim 1, wherein in the continuously performing the bypassarithmetic coding, the bypass arithmetic coding is performed on thesao_band_position after the bypass arithmetic coding is performed on thesao_offset_sign and without performing the context adaptive binaryarithmetic coding on information after the bypass arithmetic coding isperformed on the sao_offset_sign.
 3. A moving picture coding apparatuswhich codes an input image to generate a bit stream, the moving picturecoding apparatus comprising: a first coding unit which performs contextadaptive binary arithmetic coding in which a variable probability valueis used on, from among multiple types of sample adaptive offset (SAO)information used for SAO that is a process of assigning an offset valueto a pixel value of a pixel included in an image generated by coding theinput image, part of sao_type_idx indicating that the SAO is not to beperformed; and a second coding unit which continuously performs bypassarithmetic coding in which a fixed probability value is used on, fromamong the multiple types of the SAO information, (i) sao_band_positionindicating a range of pixel values to which the SAO is applied and (ii)sao_offset_sign indicating whether the offset value is positive ornegative, wherein, in the bitstream, the coded sao_band_position and thecoded sao_offset_sign are placed after the coded sao_type_idx, andwherein a variable probability is not used in the bypass arithmeticcoding.
 4. A moving picture coding apparatus which codes an input imageto generate a bit stream, the moving picture coding apparatuscomprising: processing circuitry; and a storage coupled to theprocessing circuitry, wherein the processing circuitry performs thefollowing using the storage: performing context adaptive binaryarithmetic coding in which a variable probability value is used on, fromamong multiple types of sample adaptive offset (SAO) information usedfor SAO that is a process of assigning an offset value to a pixel valueof a pixel included in an image generated by coding the input image,part of sao_type_idx indicating that the SAO is not to be performed; andcontinuously performing bypass arithmetic coding in which a fixedprobability value is used on, from among the multiple types of the SAOinformation, (i) sao_band_position indicating a range of pixel values towhich the SAO is applied and (ii) sao_offset_sign indicating whether theoffset value is positive or negative, wherein, in the bitstream, thecoded sao_band_position and the coded sao_offset_sign are placed afterthe coded sao_type_idx, and wherein a variable probability is not usedin the bypass arithmetic coding.